U.S. patent application number 11/758796 was filed with the patent office on 2008-02-21 for polyimide solvent cast films having a low coefficient of thermal expansion and method of manufacture thereof.
Invention is credited to Kwok Pong Chan, Erik Hagberg, Tara J. Mullen, Roy Ray Odle.
Application Number | 20080044683 11/758796 |
Document ID | / |
Family ID | 39101734 |
Filed Date | 2008-02-21 |
United States Patent
Application |
20080044683 |
Kind Code |
A1 |
Chan; Kwok Pong ; et
al. |
February 21, 2008 |
POLYIMIDE SOLVENT CAST FILMS HAVING A LOW COEFFICIENT OF THERMAL
EXPANSION AND METHOD OF MANUFACTURE THEREOF
Abstract
A solvent cast film comprises a polyimide comprising structural
units derived from polymerization of a dianhydride component
comprising a dianhydride selected from the group consisting of
3,4'-oxydiphthalic dianhydride, 3,3'-oxydiphthalic dianhydride,
4,4'-oxydiphthalic dianhydride, and combinations thereof, with a
diamine component comprising 4,4'-diaminodiphenylsulfone; wherein
the polyimide has a glass transition temperature from 190.degree.
C. to 400.degree. C.; and wherein the film has a coefficient of
thermal expansion of less than 60 ppm/.degree. C., a thickness from
0.1 to 250 micrometers, endless than 5% residual solvent by
weight.
Inventors: |
Chan; Kwok Pong; (Troy,
NY) ; Hagberg; Erik; (Evansville, IN) ;
Mullen; Tara J.; (Mt. Vernon, IN) ; Odle; Roy
Ray; (Mt. Vernon, IN) |
Correspondence
Address: |
SABIC - 08CU - ULTEM;SABIC Innovative Plastics - IP Legal
ONE PLASTICS AVENUE
PITTSFIELD
MA
01201-3697
US
|
Family ID: |
39101734 |
Appl. No.: |
11/758796 |
Filed: |
June 6, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60805821 |
Jun 26, 2006 |
|
|
|
Current U.S.
Class: |
428/626 ;
428/220; 524/493; 525/451; 528/335; 528/348 |
Current CPC
Class: |
C08J 2379/08 20130101;
Y10T 428/31721 20150401; Y10T 428/31678 20150401; H05K 2201/0209
20130101; H05K 1/0346 20130101; C08L 79/08 20130101; Y10T 428/31681
20150401; Y10T 428/25 20150115; H05K 2201/0257 20130101; H05K
2201/068 20130101; C08G 73/1007 20130101; H05K 1/0373 20130101;
Y10T 428/12569 20150115; C08J 5/18 20130101; H05K 2201/0154
20130101 |
Class at
Publication: |
428/626 ;
428/220; 524/493; 525/451; 528/335; 528/348 |
International
Class: |
B32B 15/088 20060101
B32B015/088; B32B 5/00 20060101 B32B005/00; C08G 69/26 20060101
C08G069/26; C08K 3/34 20060101 C08K003/34 |
Claims
1. A solvent cast film, comprising: a polyimide comprising
structural units derived from polymerization of a dianhydride
component comprising a dianhydride selected from the group
consisting of 3,4'-oxydiphthalic dianhydride, 3,3'-oxydiphthalic
dianhydride, 4,4'-oxydiphthalic dianhydride, and a combination
thereof, with a diamine component comprising
4,4'-diaminodiphenylsulfone; wherein the polyimide has a glass
transition temperature from 190.degree. C. to 400.degree. C.; and
wherein the film has a coefficient of thermal expansion of less
than 60 ppm/.degree. C., a thickness from 0.1 to 250 micrometers,
and less than 5% residual solvent by weight.
2. The film of claim 1, wherein the dianhydride component further
comprises a dianhydride selected from the group consisting of:
2,2'-bis(1,3-trifluoromethyl-4-phenyl)-3,3',4,4'-biphenyltetracarboxylic
dianhydride
2,2'-bis(1-methyl-4-phenyl)-3,3',4,4'-biphenyltetracarboxylic
dianhydride;
2,2'-bis(1-phenyl-4-phenyl)-3,3',4,4'-biphenyltetracarboxylic
dianhydride;
2,2'-bis(1-trifluoromethyl-2-phenyl)-3,3',4,4'-biphenyltetracarboxylic
dianhydride;
2,2'-bis(1-trifluoromethyl-3-phenyl)-3,3',4,4'-biphenyltetracarboxylic
dianhydride;
2,2'-bis(1-trifluoromethyl-4-phenyl)-3,3',4,4'-biphenyltetracarboxylic
dianhydride; 2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane
dianhydride;
2,2-bis((4-(3,3-dicarboxyphenoxy)phenyl)hexafluoropropane
dianhydride; 2,2-bis((4-(3,3-dicarboxyphenoxy)phenyl)propane
dianhydride; 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane
dianhydride; 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane
dianhydride; 2,2'-dibromo-3,3',4,4'-biphenyltetracarboxylic
dianhydride; 2,3,6,7-naphthalic dianhydride;
3,3',4,4'-benzophenonetetracarboxylic dianhydride;
3,3',4,4'-biphenylethertetracarboxylic dianhydride;
3,3',4,4'-biphenylsulphonictetracarboxylic dianhydride;
3,3',4,4'-biphenyltetracarboxylic dianhydride;
3,3',4,4'-dimethyldiphenylsilane tetracarboxylic dianhydride;
3,3',4,4'-diphenylmethane tetracarboxylic dianhydride;
3,3',4,4'-diphenylsulfide tetracarboxylic dianhydride;
3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride;
3,3',4,4'-diphenylsulfoxide tetracarboxylic dianhydride;
3,3'-benzophenone tetracarboxylic dianhydride; 3,3'-oxydiphthalic
dianhydride; 3,4'-oxydiphthalic dianhydride;
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)benzophenone
dianhydride;
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenylether
dianhydride;
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenylsulfide
dianhydride;
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenylsulfone
dianhydride;
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl-2,2-propane
dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)benzophenone
dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)diphenylether
dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)diphenylsulfide
dianhydride; 4,4'-bis(2,3-dicarboxyphenoxy)diphenylsulfone
dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane
dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfide
dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulphone
dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)benzophenone
dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenylether
dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfide
dianhydride; 4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfone
dianhydride; 4,4'-bisphenol A dianhydride; 4,4'-carbonyldiphthalic
dianhydride; 4,4'-oxydiphthalic dianhydride;
6,6'-bis(3,4-dicarboxyphenoxy)-2,2',3,3'-tetrahydro-3,3,3',3'-tetramethyl-
-1,1'-spirobi[1H-indene]dianhydride;
7,7'-bis(3,4-dicarboxyphenoxy)-3,3',4,4'-tetrahydro-4,4,4',4'-tetramethyl-
-2,2'-spirobi[2H-1-benzopyran]dianhydride;
bis(phthalic)phenylsulphineoxide dianhydride;
bis(triphenylphthalic)-4,4'-diphenylether dianhydride;
bis(triphenylphthalic)-4,4'-diphenylmethane dianhydride;
hydroquinone diphthalic dianhydride;
m-phenylene-bis(triphenylphthalic) dianhydride;
p-phenylene-bis(triphenylphthalic) dianhydride; pyromellitic
dianhydride; (3,3',4,4'-diphenyl)phenylphosphinetetracarboxylic
dianhydride;
(3,3',4,4'-diphenyl)phenylphosphineoxidetetracarboxylic
dianhydride; 1,3-bis(2,3-dicarboxyphenoxy)benzene dianhydride;
1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride;
1,4-bis(2,3-dicarboxyphenoxy)benzene dianhydride;
1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride; and a combination
thereof.
3. The film of claim 1, wherein the diamine component further
comprises a diamine selected from the group consisting of:
1,5-diaminonaphthalene;
2,2',3,3'-tetrahydro-3,3,3',3'-tetramethyl-1,1'-spirobi[1H-indene]-6,6'-d-
iamine; 2,4-diaminotoluene; 2,6-diaminotoluene;
3,3',4,4'-tetrahydro-4,4,4',4'-tetramethyl-2,2'-spirobi[2H-1-benzopyran]--
7,7'-diamine; 3,3'-dimethoxybenzidine; 3,3'-dimethylbenzidine;
4,4'-diaminodiphenylether(4,4'-oxydianiline);
4,4'-diaminodiphenylsulfide;
4,4'-diaminodiphenylmethane(4,4'-methylenedianiline);
4,4'-diaminodiphenylpropane; benzidine; bis(4-aminophenyl)ether;
bis(4-aminophenyl)sulfide; bis(4-aminophenyl)sulfone;
bis(4-aminophenyl)methane; bis(4-aminophenyl)propane;
m-phenylenediamine; m-xylylenediamine; p-phenylenediamine;
p-xylylenediamine; and a combination thereof.
4. The film of claim 1, wherein the diamine component further
comprises a diamine selected from the group consisting of
m-phenylenediamine, p-phenylenediamine, 4,4'-oxydianiline,
1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, and
a combination thereof.
5. The film of claim 1, wherein the solvent comprises
N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrolidinone,
dimethylsulfoxide, sulfolane, tetrahydrofuran, benzophenone,
cyclohexanone, phenol, o-cresol, p-cresol, m-cresol, phenol,
ethylphenol, isopropylphenol, t-butylphenol, xylenol, mesitol,
chlorophenol, dichlorophenol, phenylphenol, a monoalkyl ether of
ethylene glycol having from 1 to about 4 carbon atoms in the alkyl
group, a monoalkyl ether of diethylene glycol having from 1 to
about 4 carbon atoms in the alkyl group, a monoaryl ether glycol, a
monoaryl ether of propylene glycol, tetramethylurea, phenoxy
ethanol, propylene glycol phenyl ether, anisole, veratrole,
o-dichlorobenzene, chlorobenzene, trichloroethane, methylene
chloride, chloroform, pyridine, N-cyclohexylpyrrolidinone, ethyl
lactate, an ionic liquid, and a combination thereof.
6. The film of claim 1, wherein the film further comprises a
nanoclay.
7. The film of claim 6, wherein the film has a lower CTE than a
film of the same composition without the nanoclay.
8. The film of claim 6, wherein the film has a Tg that is the same
as a film of the same composition without the nanoclay.
9. The film of claim 6, wherein the film is transparent.
10. The film of claim 1, wherein the film has a coefficient of
thermal expansion of at least 5 ppm/.degree. C.
11. The film of claim 1, wherein the film has a coefficient of
thermal expansion from 10 to 30 ppm/.degree. C.
12. The film of claim 1, wherein the film has a coefficient of
thermal expansion from 10 to 20 ppm/.degree. C.
13. The film of claim 1, wherein the film has a coefficient of
thermal expansion that is within .+-.20 ppm/.degree. C. of the
coefficient of thermal expansion of copper, silicon, aluminum,
gold, silver, nickel, a glass, a ceramic, or a polymer.
14. The film of claim 1, wherein the film has a coefficient of
thermal expansion that is within .+-.15 ppm/.degree. C. of the
coefficient of thermal expansion of copper.
15. The film of claim 1, wherein the film loses less than 5% of its
initial weight after storage in water for 24 hours at 25.degree.
C.
16. The film of claim 1, wherein the film loses less than 2% of its
initial weight after storage in water for 24 hours at 25.degree.
C.
17. The film of claim 1, wherein the film is a dry film, and a 10
wt % solution of the dried film in dimethylacetamide or
N-methylpyrolidinone has an inherent viscosity that is greater than
0.05 dl/g.
18. The film of claim 1, wherein after lamination to a substrate at
a temperature from 250.degree. C. to 450.degree. C., the
coefficient of thermal expansion of the laminated film is within
.+-.10 ppm/.degree. C. of the coefficient of thermal expansion of
the film prior to lamination.
19. The film of claim 1, wherein the film is cast from a
composition comprising 1 to 30 wt % solids.
20. The film of claim 1, further comprising up to 50 wt % of a
recycled polyimide film comprising structural units derived from
the dianhydride component and a diamine component, wherein prior to
recycling the polyimide has a glass transition temperature from
210.degree. C. to 450.degree. C.; and the film has a coefficient of
thermal expansion of less than 60 ppm/.degree. C., a thickness from
1 to 250 micrometers, and less than 5% residual solvent by
weight.
21. The film of claim 1, wherein the film further comprises up to
30 wt % of a recycled polyimide film comprising structural units
derived from the dianhydride component and a diamine component,
wherein prior to recycling the polyimide has a glass transition
temperature from 210.degree. C. to 450.degree. C.; and the film has
a coefficient of thermal expansion of less than 60 ppm/.degree. C.,
a thickness from 1 to 250 micrometers, and less than 5% residual
solvent by weight.
22. The film of claim 20, wherein the coefficient of thermal
expansion of the film comprising the recycled polyimide film is
within 10 ppm/.degree. C. of the coefficient of thermal expansion
of the film without the recycled polyimide film.
23. A composition comprising a recycled polyimide film of claim
1.
24. The composition of claim 23, wherein the recycled polyimide
film is capable of being melt blended.
25. A method of making a solvent cast polyimide film, comprising:
casting a polyamic acid composition onto a substrate to form a
film; heating the cast film for a time and at a temperature
effective to remove the solvent and to form a solvent cast
polyimide film having a coefficient of thermal expansion of less
than 60 ppm/.degree. C. and a thickness from 0.1 to 125
micrometers; and processing the solvent cast polyimide film to
reduce the coefficient of thermal expansion of the film to below 35
ppm/.degree. C.
26. The method of claim 25, wherein processing the solvent cast
polyimide film to reduce the coefficient of thermal expansion of
the film comprises biaxially stretching the solvent cast polyimide
film.
27. The method of claim 25, wherein the solvent cast polyimide film
comprises a nanoclay.
28. The method of claim 25, wherein the nanoclay is an exfoliated
nanoclay.
29. The method of claim 28, wherein exfoliating is carried out in a
composition comprising 10-90% by weight of the nano-clay and 10-90%
by weight of the solvent system.
30. The method of claim 27, wherein the nanoclay is added to the
polyamic acid composition after the polyamic acid composition is
formed.
31. The method of claim 25, further comprising reacting a
dianhydride component and an organic diamine component in a solvent
system to form the polyamic acid composition before casting the
polyamic acid composition.
32. The method of claim 31, comprising reacting the dianhydride
component and the organic diamine component in the presence of the
nanoclay.
33. The method of claim 31, further comprising exfoliating the
nanoclay in the solvent system prior to reacting the dianhydride
component and the organic diamine component in the solvent
system.
34. An article comprising the film of claim 1.
35. The article of claim 34, wherein the film is disposed on a
first substrate.
36. The article of claim 35, wherein the first substrate is
selected from the group consisting of copper, silicon, aluminum,
gold, silver, nickel, a glass, a ceramic, and a polymer.
37. The article of claim 36, wherein the polymer is a solvent cast
polyimide film comprising structural units derived from
polymerization of a dianhydride component comprising a dianhydride
selected from the group consisting of 3,4'-oxydiphthalic
dianhydride, 3,3'-oxydiphthalic dianhydride, 4,4'-oxydiphthalic
dianhydride, and combinations thereof, with a diamine component;
wherein the polyimide has a glass transition temperature of at
least 190.degree. C.; wherein the film has a coefficient of thermal
expansion of less than 60 ppm/.degree. C., a thickness from 0.1 to
250 micrometers, and less than 5% residual solvent by weight;
wherein the polyimide has less than 15 molar % of structural units
derived from a member selected from the group consisting of
biphenyltetracarboxylic acid, a dianhydride of
biphenyltetracarboxylic acid, an ester of biphenyltetracarboxylic
acid, and a combination thereof.
38. The article of claim 35, further comprising a second substrate
disposed on a side of the film opposite the first substrate.
39. The article of claim 38, wherein the second substrate is
selected from the group consisting of copper, silicon, aluminum,
gold, silver, nickel, glass, ceramic, a polymer, and a combination
thereof.
40. The article of claim 39, wherein the polymer is a solvent cast
polyimide film comprising structural units derived from
polymerization of a dianhydride component comprising a dianhydride
selected from the group consisting of 3,4'-oxydiphthalic
dianhydride, 3,3'-oxydiphthalic dianhydride, 4,4'-oxydiphthalic
dianhydride, and combinations thereof, with a diamine component;
wherein the polyimide has a glass transition temperature of at
least 190.degree. C.; wherein the film has a coefficient of thermal
expansion of less than 60 ppm/.degree. C., a thickness from 0.1 to
250 micrometers, and less than 5% residual solvent by weight;
wherein the polyimide has less than 15 molar % of structural units
derived from a member selected from the group consisting of
biphenyltetracarboxylic acid, a dianhydride of
biphenyltetracarboxylic acid, an ester of biphenyltetracarboxylic
acid, and a combination thereof.
41. A solvent cast film, comprising: a polyetherimide comprising
structural units derived from the polymerization of a dianhydride
component comprising a dianhydride selected from the group
consisting 3,4'-oxydiphthalic dianhydride, 3,3'-oxydiphthalic
dianhydride, 4,4'-oxydiphthalic dianhydride, and combinations
thereof, with a diamine component comprising
4,4'-diaminodiphenylsulfone; wherein the polyimide has a glass
transition temperature from 190.degree. C. to 400.degree. C.;
wherein the film has a coefficient of thermal expansion of less
than 60 ppm/.degree. C., a thickness from 0.1 to 250 micrometers,
and less than 5% residual solvent by weight; wherein the film has a
coefficient of thermal expansion that is within .+-.20 ppm/.degree.
C. of the coefficient of thermal expansion of copper, silicon,
aluminum, gold, silver, nickel, a glass, a ceramic, or a polymer;
and wherein the solvent is selected from the group consisting of
N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrolidinone,
dimethylsulfoxide, sulfolane, tetrahydrofuran, benzophenone,
cyclohexanone, phenol, o-cresol, p-cresol, m-cresol, phenol,
ethylphenol, isopropylphenol, t-butylphenol, xylenol, mesitol,
chlorophenol, dichlorophenol, phenylphenol, a monoalkyl ether of
ethylene glycol having from 1 to about 4 carbon atoms in the alkyl
group, a monoalkyl ether of diethylene glycol having from 1 to
about 4 carbon atoms in the alkyl group, a monoaryl ether glycol, a
monoaryl ether of propylene glycol, tetramethylurea, phenoxy
ethanol, propylene glycol phenyl ether, anisole, veratrole,
o-dichlorobenzene, chlorobenzene, trichloroethane, methylene
chloride, chloroform, pyridine, N-cyclohexylpyrrolidinone, ethyl
lactate, an ionic liquid, and a combination comprising at least two
of the foregoing solvents.
42. A solvent cast film comprising a polyetherimide comprising
structural units derived from polymerization of 4,4'-oxydiphthalic
dianhydride, and 4,4'-diaminodiphenylsulfone; wherein the polyimide
has a glass transition temperature from 190.degree. C. to
400.degree. C.; wherein the film has a coefficient of thermal
expansion of less than 60 ppm/.degree. C., a thickness from 0.1 to
250 micrometers, and less than 5% residual solvent by weight; and
wherein the film has less than 15 molar % of
biphenyltetracarboxylic acid or its dianhydride or its ester.
43. A method of manufacture of a recycled polyimide composition,
comprising melting the solvent cast polyimide film of claim 1; and
combining the melted solvent cast polyimide film of claim 1 with a
polymer composition to form a recycled a polyimide composition.
44. The method of claim 43, further comprising extruding the
composition comprising the melted film.
45. A method of manufacture of a recycled a polyimide composition,
comprising dissolving the solvent cast polyimide film of claim 1;
and combining the dissolved film of claim 1 with a polymer
composition to form the recycled polyimide composition.
46. The method of claim 45, further comprising extruding the
recycled polyimide composition.
47. An article comprising the recycled polyimide composition of
claim 43.
48. An article comprising the recycled polyimide composition of
claim 45.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to copending U.S.
Provisional Application Ser. No. 60/805,821, filed Jun. 26, 2006,
which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention is directed to a solvent cast film
comprising a polyimide and methods for the manufacture of such
films. The film is formed by polymerization of a dianhydride
component and a diamine component, and has a Tg of between
180.degree. C. and 450.degree. C., specifically 190.degree. C. or
greater, and wherein the film has: a) a CTE of less than 70
ppm/.degree. C., specifically less than 60 ppm/.degree. C.; b) a
thickness of between 0.1 micrometers and 250 micrometers,
specifically 5 to 250 micrometers ; and, c) contains less than 5%
residual solvent by weight.
BACKGROUND OF THE INVENTION
[0003] Thermoplastic sheets and films have a broad range of
applications. For instance, thermoplastic films and sheets can be
found in automotive applications, electronic applications, military
applications, appliances, industrial equipment, and furniture.
[0004] Thermoplastic sheets and film can be reinforced or
non-reinforced, porous or nonporous and can comprise a single
thermoplastic or multiple thermoplastics. When a thermoplastic
sheet or film comprises multiple thermoplastics it may be as a
blend, as layers, or both.
[0005] One important use of films is their use as substrates, or
coatings on, flexible circuit applications. In order to serve in
this role a new film should meet two requirements critical for
flexible circuit substrates, namely low coefficient of thermal
expansion (CTE) and high temperature survivability (especially when
a high temperature fabrication step is employed).
[0006] Low CTE is necessary to match, as closely as possible, the
CTE of copper (CTE=17 ppm/.degree. C.). This keeps the film from
curling upon temperature change when the film is a substrate for a
copper layer, or copper circuit traces. Low CTE also prevents
unmatched changes in dimension between the copper and substrate
layers upon thermal cycling, which increases the lifetime of the
final flexible circuit by reducing stress and fatigue on the
patterned copper traces. In other words, the properties of flexible
circuit boards are benefited when their film substrate and applied
conductive metal layer expand and contract at the same rate. When
these layers don't expand and contract at the same rate issues
regarding the adherence, and orientation of the layers can and do
arise. While a CTE of less than 70 ppm/.degree. C., specifically
less than 60 ppm/.degree. C., even more specifically less than 30
ppm/.degree. C. will allow low warpage upon thermal cycling and is
a common goal, better results will be achieved as the CTE of the
film becomes closer to the CTE of copper.
[0007] A TMA or Thermomechanical Analysis tests CTE. The dimension
change of a film sample is determined as a function of temperature,
and from the slope of this change, the CTE is calculated.
Typically, the CTE must be measured for the temperature range that
the film is expected to see during flex circuit processing. A
temperature range of 20 to 250.degree. C. is a reasonable
temperature range for determination of the CTE.
[0008] High temperature survivability can also be an important
property for the substrate film to survive the soldering process
during flex circuit fabrication. The film should exhibit
survivability for short periods at elevated temperatures of, for
example, 260.degree. C. for new lead-free soldering processes. The
standard test for temperature survivability is the solder float
test, where a small piece of film is affixed to a cork and is
immersed for 10 seconds in molten solder. The film is then removed,
the solder is wiped off, and the film is examined. If there is any
visible warpage or bubbling, the film fails the test. While there
is not a standard thickness for this test, the minimum thickness at
which the film passes the solder float test can be reported.
Temperatures of 260.degree. C. and 288.degree. C. are standard
solder float temperatures for lead-eutectic and lead-free solders,
respectively.
[0009] Low CTE and high temperature resistance requirements for
flexible circuit substrates have been addressed through the use of
polyimide films. Many commercial polyimide (PI) films have a high
glass transition temperature (greater than 350.degree. C.), and can
be partially crosslinked, giving exceptional temperature
survivability. The polymer molecules in these films are stressed
slightly as they are produced, leading to alignment of the polymer
molecules and giving PI films a low CTE. Since the films never see
temperatures above the glass transition temperature (Tg) of the
material, the stress is never able to relax and the films are
dimensionally stable at flex fabrication temperatures.
[0010] As thermoplastic sheets and films are used in an increasing
wide array of applications the need for thermoplastic sheets and
films that can withstand elevated temperatures for appropriate
periods of time without substantial degradation is growing. There
is a continuing need for films having: a) a CTE under seventy
ppm/.degree. C., specifically under thirty ppm/.degree. C. and as
close to the CTE of copper as technically possible; and b) high
thermal survivability.
SUMMARY OF THE INVENTION
[0011] The present disclosure is directed to thermoplastic sheets
and films that have a broad range of applications. For instance,
thermoplastic films and sheets can be found in automotive
applications, electronic applications, military applications,
appliances, industrial equipment, and furniture.
[0012] In one embodiment, a solvent cast film comprises a polyimide
comprising structural units derived from polymerization of a
dianhydride component comprising a dianhydride selected from the
group consisting of 3,4'-oxydiphthalic dianhydride,
3,3'-oxydiphthalic dianhydride, 4,4'-oxydiphthalic dianhydride, and
combinations thereof, with a diamine component comprising
4,4'-diaminodiphenylsulfone; wherein the polyimide has a glass
transition temperature from 190.degree. C. to 400.degree. C.; and
wherein the film has a coefficient of thermal expansion of less
than 60 ppm/.degree. C., a thickness from 0.1 to 250 micrometers,
and less than 5% residual solvent by weight.
[0013] A method of making a solvent cast polyimide film comprises
casting a polyamic acid composition onto a substrate to form a
film; heating the cast film for a time and at a temperature
effective to remove the solvent and to form a solvent cast
polyimide film having a coefficient of thermal expansion of less
than 60 ppm/.degree. C. and a thickness from 0.1 to 125
micrometers; and processing the solvent cast polyimide film to
reduce the coefficient of thermal expansion of the film to below 35
ppm/.degree. C.
[0014] In still another embodiment, a solvent cast film comprises a
polyetherimide comprising structural units derived from the
polymerization of a dianhydride component comprising a dianhydride
selected from the group consisting 3,4'-oxydiphthalic dianhydride,
3,3'-oxydiphthalic dianhydride, 4,4'-oxydiphthalic dianhydride, and
combinations thereof, with a diamine component with a diamine
component comprising 4,4'-diaminodiphenylsulfone; wherein the
polyimide has a glass transition temperature from 190.degree. C. to
400.degree. C.; wherein the film has a coefficient of thermal
expansion of less than 60 ppm/.degree. C., a thickness from 0.1 to
250 micrometers, and less than 5% residual solvent by weight;
wherein the film has a coefficient of thermal expansion that is
within +20 ppm/.degree. C. of the coefficient of thermal expansion
of copper, silicon, aluminum, gold, silver, nickel, a glass, a
ceramic, or a polymer; and wherein the solvent is selected from the
group consisting of N,N-dimethylacetamide, N,N-dimethylformamide,
N-methylpyrolidinone, dimethylsulfoxide, sulfolane,
tetrahydrofuran, benzophenone, cyclohexanone, phenol, o-cresol,
p-cresol, m-cresol, phenol, ethylphenol, isopropylphenol,
t-butylphenol, xylenol, mesitol, chlorophenol, dichlorophenol,
phenylphenol, a monoalkyl ether of ethylene glycol having from 1 to
about 4 carbon atoms in the alkyl group, a monoalkyl ether of
diethylene glycol having from 1 to about 4 carbon atoms in the
alkyl group, a monoaryl ether glycol, a monoaryl ether of propylene
glycol, tetramethylurea, phenoxy ethanol, propylene glycol phenyl
ether, anisole, veratrole, o-dichlorobenzene, chlorobenzene,
trichloroethane, methylene chloride, chloroform, pyridine,
N-cyclohexylpyrrolidinone, ethyl lactate, an ionic liquid, and a
combination comprising at least two of the foregoing solvents.
[0015] In another embodiment, a solvent cast film comprises a
polyetherimide comprising structural units derived from
polymerization of 4,4'-oxydiphthalic dianhydride, and
4,4'-diaminodiphenylsulfone; wherein the polyimide has a glass
transition temperature from 190.degree. C. to 400.degree. C.;
wherein the film has a coefficient of thermal expansion of less
than 60 ppm/.degree. C., a thickness from 0.1 to 250 micrometers,
endless than 5% residual solvent by weight; and wherein the film
has less than 15 molar % of biphenyltetracarboxylic acid or its
dianhydride or its ester.
[0016] A method of manufacture of a recycled a polyimide
composition comprises melting the solvent cast polyimide film; and
combining the melted solvent cast polyimide film with a polymer
composition to form a recycled polyimide composition.
[0017] Another method of manufacture of a recycled a polyimide
composition comprises dissolving the solvent cast polyimide film;
and combining the dissolved film with a polymer composition to form
the recycled polyimide composition.
[0018] An article comprising the recycled polyimide composition is
also described.
BRIEF DESCRIPTION OF THE DRAWING
[0019] FIG. 1 is a graph of the time/temperature imidization
profile used to prepare polyetherimides.
DETAILED DESCRIPTION OF THE INVENTION
[0020] As thermoplastic sheets and films are used in the
specification and the claims which follow, reference will be made
to a number of terms which shall be defined to have the following
meanings. The singular forms "a," "an," and "the" include plural
referents unless the context clearly dictates otherwise. Unless
defined otherwise, technical and scientific terms used herein have
the same meaning as is commonly understood by one of skill in the
art. Compounds are described using standard nomenclature.
[0021] Other than in the operating examples or where otherwise
indicated, all numbers or expressions referring to quantities of
ingredients, reaction conditions, and the like, used in the
specification and claims are to be understood as modified in all
instances by the term "about." The term "combination thereof" means
that one or more of the listed components is present, optionally
together with one or more like components not listed. Various
numerical ranges are disclosed in this patent application. Because
these ranges are continuous, they include every value between the
minimum and maximum values. Unless expressly indicated otherwise,
the various numerical ranges specified in this application are
approximations. The endpoints of all ranges directed to the same
component or property are inclusive of the endpoint and
independently combinable.
[0022] For purposes of the present invention, a "film" is a flat
section of thermoplastic resin or other material that is extremely
thin in comparison to its length and breadth.
[0023] The term "casting" refers to a process of molding or forming
wherein impressions are made with fluent or molten materials as by
pouring into a mold or onto a sheet with hardening or setting of
said material in said mold or on said sheet.
[0024] A "solvent cast film" is a film formed through the casting
of fluids on a forming surface to form a sheet or web with removal
of solvent from the cast liquid.
[0025] All ASTM tests and data are from the 1991 edition of the
Annual Book of ASTM Standards unless otherwise indicated.
[0026] "Coefficient of thermal expansion" is the increment in
volume of a unit volume of polymer for a rise of temperature of
1.degree. C. at constant pressure. For the present invention CTE
measurements were performed by thermo-mechanical analysis (TMA)
with a thermal ramp rate of 5.degree. C./minute. Test specimen
dimensions were 23 mm in length by 5 mm in width. Test specimens
were subjected to a first heat from 0.degree. C. to 250.degree. C.
at 5.degree. C./min heating rate and CTE values were determined
under a force of 0.05 Newtons from the slope of length change over
the temperature range from 30.degree. C. to 200.degree. C.
[0027] "Chemical resistance" is the ability of solid materials to
resist damage by chemical reactivity or solvent action, and can be
determined in accordance with ASTM Test D543-06
[0028] "Dielectric Constant" (permittivity constant): between any
two electrically charged bodies there is a force (attraction or
repulsion) that varied according to the strength of the charges, q1
and q2, the distance between the bodies, r, and a characteristic of
the medium separating the bodies (the dielectric) known as the
dielectric constant, .epsilon.. This force is given by the
equation: F=q1q2/(.epsilon.r.sup.2).
[0029] "Flexural Modulus" (flex modulus) is the ratio, within the
elastic limit, of the applied stress in the outermost fibers of a
test specimen in three-point, static flexure, to the calculated
strain in those outermost fibers, and can be determined according
to ASTM Test D790 or D790M.
[0030] "Flexural Strength" (flexural modulus of rupture) is the
maximum calculated stress in the outermost fibers of a test bar
subjected to three-point loading at the moment of cracking or
breaking. ASTM Test D 790 and D 790M are widely used for measuring
this property. For most plastics, flexural strength is usually
substantially higher than the straight tensile strength.
[0031] "Glass Transition" is a reversible change that occurs in an
amorphous polymer or in amorphous regions of a partly crystalline
polymer when it is heated from a very low temperature into a
certain range, peculiar to each polymer, characterized by a rather
sudden change from a hard, glassy, or brittle condition to a
flexible or elastomeric condition. Physical properties such as
coefficient of thermal expansion, specific heat, and density,
usually undergo changes in their temperature derivatives at the
same time. During the transition, the molecular chains, normally
coiled, tangled, and motionless at the lower temperatures, become
free to rotate and slip past each other.
[0032] "Glass Transition Temperature" (Tg) is the approximate
midpoint of the temperature range over which the glass transition
occurs. Tg is not obvious (like a melting point), and is detected
by changes, with rising temperature, in secondary properties such
as the rate of change with temperature of specific volume or
electrical or mechanical properties. Moreover, the observed Tg can
vary significantly with the specific property chosen for
observation and on experimental details such as the rate of heating
or electrical frequency. A reported Tg should therefore be viewed
as an estimate. The most reliable estimates are normally obtained
from the loss peak in dynamic-mechanical tests or from dilatometric
data. For purposes of the present invention, the glass transition
temperature (Tg) is determined by the maximum point of the tan
delta curve. Tg can also be determined by the inflection of the DSC
(Differential Scanning Calorimetry) trace (ASTM Test D3148).
[0033] "Melting Temperature" (hereafter identified by its symbol
"T.sub.m") is the temperature at which the thermal energy in a
solid material is sufficient to overcome the intermolecular forces
of attraction in the crystalline lattice so that the lattice breaks
down and the material becomes a liquid, i.e. it melts. According to
the present invention the T.sub.m is measured according to ASTM
test D3148.
[0034] "Melt Viscosity" is the resistance to shear in a molten
resin, quantified as the quotient of shear stress divided by shear
rate at any point in the flowing material. Elongational viscosity,
which comes into play in the drawing of extrudates, is analogously
defined. In polymers, the viscosity depends not only on temperature
and, less strongly, on pressure, but also on the level of shear
stress (or shear rate). For purposes of the present invention melt
viscosity is determined at 380.degree. C. as measured by capillary
rheology according to ASTM D3835.
[0035] "Moisture Absorption" is the pickup of water vapor by a
material upon exposure for a definite time interval in an
atmosphere of specified humidity and temperature. No ASTM test
exists for this property. Moisture absorption at 50% relative
humidity and by immersion in water is measured by weight gain.
[0036] "Tensile Modulus" or "Modulus of Elasticity" is the ratio of
nominal tensile stress to the corresponding elongation below the
proportional limit of the material. The relevant ASTM test is
D638.
[0037] "Tensile Strength" is the maximum nominal stress sustained
by a test specimen being pulled from both ends, at a specified
temperature and at a specified rate of stretching. When the maximum
nominal stress occurs at the Yield Point it shall be designated
tensile strength at yield. When it occurs at break, it shall be
designated tensile strength at break. The ASTM test for plastics is
D638 (metric, D638M). The SI unit of tensile strength is the pascal
(N/m.sup.2).
[0038] Gallery spacing or d-spacing is the distance between the
various microplates that make up a nanosilicate (synonymous with
nano-clay, nano clay, or nanoclay). The changes in the gallery
spacing appear to be dependent on the composition of the modified
nanosilicate and the solvent.
[0039] "Intercalate" refers to a process by which the d-spacing is
increased by the incorporation of a modifier, solvent, or a polymer
between the plates. A modified nano clay has a d-spacing that is
greater than that for the same unmodified nano clay.
[0040] "Exfoliate" refers to the complete separation of the plates
that make up the clay structure. Sometimes there is incomplete
exfoliation to smaller structures that have multiple plate that are
called tactoids.
[0041] "Polyamic acid solution" (also known as poly-amide-acid,
poly(amic acid), amic acid, polyamicacid, poly (amic acid),
poly(amide acid), poly(amic) acid, poly(amide-acid), or
polyamic-acid) is a solution containing amic acid units that have
the capability of reacting with surrounding organic moieties to
form imide groups.
[0042] "Polyimide" as used herein refers to polymers comprising
repeating imide functional groups, and optionally additional
functional groups such as amides and/or ethers. "Polyimide"
accordingly includes within its scope polyamide imides and
polyetherimides.
[0043] The term "inerted" means that the atmosphere in a container
is replaced with an inert gas, such as for example, nitrogen.
[0044] "Recycle" means that all or a part of the polymer according
to the present invention can be re-used for the original utility
for which the polymer was made. For example, if the original use of
the polymer as a solvent cast film for a flexible circuit board,
all or part of the polymer can be recycled and be re-dissolved in
solvent with or without the use of additional monomer or polymer.
Recycle can also mean that the polymer can be re-used either in
part or completely by another reprocessing method into another
utility such as an injected molded part.
[0045] When structural units of chemical moieties are said to be
formally derived from a precursor moiety herein, there is no
implied limitation on the actual chemical reaction which may be
used to produce the chemical moiety. For example when a chemical
moiety such as a polyetherimide is said to have structural units
formally derived from a dianhydride and a diamine, then any known
method could be used to prepare the polyetherimide, including
reaction of a dianhydride and a diamine, or a displacement reaction
between a phenoxide species and an imide bearing a displaceable
group, or other known method, it only being necessary that the
chemical moiety comprise structural units which may be represented
in the stated precursor moiety.
[0046] The present disclosure is directed to solvent cast films
comprising a dianhydride component comprising a dianhydride
selected from the group consisting of 3,4'-oxydiphthalic
dianhydride, 3,3'-oxydiphthalic dianhydride, 4,4'-oxydiphthalic
dianhydride, and combinations thereof, and a diamine component
comprising 4,4'-diaminodiphenylsulfone, wherein the polyimide has a
Tg from 180.degree. C. and 450.degree. C., specifically 190.degree.
C. or greater, and wherein the film has: a) a CTE of less than 70
ppm/.degree. C., specifically less than 60 ppm/.degree. C.; b) a
thickness of between 5 micrometers and 250 micrometers,
specifically 0.1 to 250 micrometers; and, c) contains less than 5%
residual solvent by weight.
[0047] The solvent cast film according to the present invention can
be made of at least one polyimide have a Tg of between 180.degree.
C. and 450.degree. C. In another embodiment, the polyimide has a Tg
of 190.degree. C. or greater, specifically 190.degree. C. to
500.degree. C., more specifically 190.degree. C. to 400.degree. C.
The skilled artisan will appreciate that the Tg of any particular
polyimide can vary widely depending upon factors including the
choice of dianhydride monomer, the number of different dianhydride
monomers (structures as opposed to units), the choice of diamine
monomer, the number of different diamine monomers (structures as
opposed to units), processing conditions during production of the
film, type of imidization process used to cure the polymer, etc.
The skilled artisan will appreciate the ability to create a polymer
having a desired Tg anywhere within the aforementioned range of
Tg's, depending on the monomers used, the use of endcapping,
etc.
[0048] The type of polyimide making up the film is similarly
variable. The present invention specifically includes random and
block polymers and co-polymers in all combinations of the one or
more dianhydride and the one or more diamine from which the present
polyimides can be made. More than one type of polyimide can be
present, for example a combination of a polyamideimide and a
polyetherimide, or two different kinds of polyetherimide. Also, the
present invention is directed to solvent cast films comprising one
or more polyimide films that includes other polymers selected from
the group consisting of amorphous thermoplastic polymers including
PPSU (polyphenylene sulfone), PSU (polysulfone), PC
(polycarbonate), PPO (polyphenylene ether), PMMA
(polymethylmethacrylate), ABS (acrylonitrile-butadiene-styrene
terpolymer), PS (polystyrene), PVC (polyvinylchloride), crystalline
thermoplastic resins including PFA (perfluoroalkoxyalkane), MFA
(co-polymer of TFE (tetrafluoroethylene) and PFVE (perfluorinated
vinyl ether)), FEP (fluorinated ethylene propylene polymers), PPS
(polyphenylene sulfide), PEK (polyether ketone), PEEK
(polyether-ether ketone), ECTFE (ethylene-chlorotrifluoroethylene
copolymer), PVDF(polyvinylidene fluoride), PTFE
(polytetrafluoroethylene), PET (polyethylene terephthalate), POM
(polyacetal), PA (polyamide), UHMW-PE (ultra high molecular weight
polyethylene), PP (polypropylene), PE (polyethylene), HDPE (high
density polyethylene), LDPE (low density polyethylene), and
advanced engineering resins such as PBI (polybenzimidazole),
poly(ether sulfone), poly(aryl sulfone), polyphenylene ethers,
polybenzoxazoles, and polybenzothiazoles, as well as blends and
co-polymers thereof.
[0049] Measured CTE's of the films may be an inherent property of
the material by virtue of the materials chemical make-up.
Alternatively, the CTE may be significantly lower than the inherent
CTE of the film material through the use of additives and or by the
performance of additional processing steps. The CTE of the solvent
cast film can be any CTE which is below 70 ppm/.degree. C.,
specifically below 60 ppm/.degree. C., and allows the film to
function in its intended utility. For example, for a flexible
circuit board the CTE can be close enough to that of the adjacent
metallic conductive layer that the film is capable of serving its
intended utility as a dielectric substrate, a layer in a laminate
and/or a covering for a flexible circuit board. In separate
embodiments, the CTE is less than 70 ppm/.degree. C., less than 50
ppm/.degree. C., less than 40 ppm/.degree. C., less than 35
ppm/.degree. C., less than 30 ppm/.degree. C., or less than 20
ppm/.degree. C. According to other embodiments, the film has a CTE
of at least 5 ppm/.degree. C. The film can also have a CTE of 5 to
60 ppm/.degree. C., and more specifically the coefficient of
thermal expansion is 10 ppm/.degree. C. to 30 ppm/.degree. C., and
even more specifically 10 ppm/.degree. C. to 20 ppm/.degree. C.
[0050] Alternatively, the CTE of the film is adjusted to match a
substrate material on which it is disposed. In one embodiment, the
film has a CTE that is within .+-.20 ppm/.degree. C. of the CTE of
copper, silicon, aluminum, gold, silver, nickel, a glass, a
ceramic, or a polymer, specifically within .+-.20 ppm/.degree. C.
of the CTE of copper, silicon, aluminum, gold, silver, or nickel.
In another embodiment, the film has a CTE that is within .+-.15
ppm/.degree. C. of the coefficient of thermal expansion of copper,
silicon, aluminum, gold, silver, or nickel, specifically
copper.
[0051] In an advantageous feature, it has been found that the CTE
of the films is very stable. For example, the film after lamination
to a substrate at a temperature from 250 to 450.degree. C. has a
CTE within .+-.10 ppm/.degree. C. of the CTE of the film prior to
lamination.
[0052] The thickness of the films can vary widely depending upon
the end use application, the method of making the film, the solids
contents of the casting solution, to name a few of the subject
parameters. The thickness may vary from 0.1 micrometers up to
10,000 micrometers, or more particularly from 5 micrometers up to
1,000 micrometers, however it is expected that for use in flexible
circuit boards the most likely thickness will be between 0.1
micrometers and 250 micrometers.
[0053] The final solvent cast film may contain residual solvent and
still be capable of functioning for its intended purpose. The
minimum amount of residual solvent will be the most residual
solvent content under which the film will still function for its
intended utility. One the other hand, the solvent cast films may
also contain as low a residual solvent content as is possible to
achieve. For example, solvent is expensive and can be an
environmental hazard. Both a cost savings and an improvement of
environmental conditions may be achieved by minimizing the amounts
of solvent contained in final product. The residual solvent content
will be less than 5% of the total weight of the film. In another
embodiment, the amount of residual solvent will be less than 1% of
the total weight of the film.
[0054] Solvents which can be used in the process include any
solvent with which a solvent cast film may be made. The solvent can
be a good solvent for polyimides, by for example, having a
relatively high boiling to facilitate solution film formation or
direct devolatization via extrusion. The solvent for film formation
can be the same that is used to make the polyamic acid solution
described below. Examples of suitable solvents include, but are not
limited to, N-methyl pyrrolidinone(NMP), trichloroethane,
N,N-dimethylacetamide (DMAc), N-methylpyrolidinone (NMP),
dimethylsulfoxide (DMSO), sulfolane, tetrahydrofuran (THF),
benzophenone, cyclohexanone, phenol, mixtures of o-, p- and
m-cresols, mixtures of cresylic with phenol, ethylphenols,
isopropylphenols, tert-butylphenols, xylenols, mesitols,
chlorophenols, dichlorophenols, such as ortho-dichlorobenzene
(o-DCB), phenylphenols, a monoalkyl ether of ethylene glycol having
from 1 to 4 carbon atoms in the alkyl group, a monoalkyl ether of
diethylene glycol having from 1 to 4 carbon atoms in the alkyl
group, a monoaryl ether glycol, a monoaryl ether of propylene
glycol, N,N-dimethylformamide, tetramethylurea, phenoxy ethanol,
propylene glycol phenyl ether, anisole, veratrole,
o-dichlorobenzene, chlorobenzene, trichloroethane, methylene
chloride, chloroform, pyridine, N-cyclohexylpyrrolidinone, ethyl
lactate, an ionic liquid, and mixtures containing one or more of
these solvents. Ionic liquids generally include salts having a
melting point that is relatively low (below 100.degree. C.).
Examples of ionic liquids include, but and are not limited to
ammonium, imidazolium-, phosphonium-, pyridinium-, pyrrolidinium-,
and sulfonium-based salts. Counter-ions in such liquids can
include, but are not be limited to the following: bromides,
chlorides, tetrafluoroborates, acetates, phosphates, carbonates,
sulfates, methane sulfates, nitrates, thiocyanates, and
combinations thereof.
[0055] The skilled artisan will appreciate that the specific
solvent used is dependent on any number of factors including the
solubility of the polyimide and the precursor monomers in a
solvent, and the volatility of the solvent, for example.
[0056] Solvent cast films according to the present invention may be
made by any method known in the art. The following patents assigned
to GE disclose generic methods of making solvent cast films and
casting solutions: U.S. Pat. No. 4,115,341; 4,157,996; 4,307,226;
4,360,633; 4,374,972; and, 3,847,867. One manufacturing process can
involve the following steps: forming a polyamic acid solution
comprising the polyamic acid product of a monomer component
comprising one or more dianhydrides and one or more organic
diamines at least partially dissolved in a solvent system; casting
the polyamic acid solution onto a substrate such that the polyamic
acid solution takes on a form having a length, width and depth on
the surface of the substrate; removing the solvent, and curing the
polyamic acid solution, e.g., by heating the cast film for a time
and at a temperature effective to form a film having a CTE less
than 70 ppm/.degree. C., specifically less than 60 ppm/.degree. C.,
and a thickness of from 0.5 micrometers to 250 micrometers,
specifically 0.1 to 250 micrometers.
[0057] Alternatively, the method can comprise making a solvent cast
film comprising: preparing a casting solution comprising a polyamic
acid solution made up of a monomer component the forms a polyamic
acid, and a solvent component; casting a film of the casting
solution on a support base; removing solvent from the cast film for
a predetermined period of time to form a solvent cast polyimide
film having a CTE less than 70 ppm/.degree. C., specifically less
than 60 ppm/.degree. C. and a thickness of between 0.1 micrometers
and 250 micrometers, specifically between 5 and 250 micrometers;
and conducting an additional process step on the solvent cast film
to reduce the CTE of the film below 35 ppm/.degree. C.,
specifically below 30 ppm/.degree. C.
[0058] The polyamic acid solution may be prepared by mixing one or
more dianhydride(s), water, and solvent as by stirring until the
one or more dianhydride component is dissolved. Then the one or
more monomeric diamine can be added and the solution stirred until
the amines dissolve. The components which make up the dianhydride
component and the diamine component may include 1, 2, 3, 4, 5, or
more different dianhydrides and diamines. The scope of the present
invention is specifically intended to include all permutations, and
combinations of the number and variety of dianhydride and diamine
monomers. For example, in one embodiment, the polyamic acid
solution will be made up of two different dianhydrides and two
different diamines. In another embodiment, one of the one or more
dianhydrides is ODPA.
[0059] In general, the organic amine component may be included in
an amount of from 0.5 mole to 2.0 moles, or, more particularly,
from 1 to 1.3 moles, per mole of dianhydride component. Where more
than one compound is included in a component of the present
solution, the parts, moles, or other quantity of such component is
taken as the sum of the parts, moles, or such other quantity,
respectively, of each compound included in such component. Thus,
for example, total amine content is calculated by adding the
equivalent amounts of each diamine in the amine component e.g.,
2(number of moles of 1.sup.st diamine)+2(number of moles of
2.sup.nd diamine)=total equivalents of amine.
[0060] Total anhydride content is calculated in a similar fashion.
A slight excess of amine can be used to impart additional film
flexibility or possible cross-linking. It has been found that
polyimide enamel can have from 5 to 500 repeating
dianhydride-diamine reaction product units and preferably from 10
to 200. Terminal amino and phthalic acid or phthalic anhydride or
various suitable end groups can also be present.
[0061] Experience has shown that sufficient solvent should be
utilized to provide a solids content to provide a solution with a
workable viscosity for stirring and handling. In one embodiment,
the solids content will be from 1-65% by weight. In other
embodiments the solids content will be from 1-40%, 1-30%, 1-25%,
1-15%, or 1-12.5% by weight.
[0062] Solutions having high ratios of monomeric reactants to
organic solvent component advantageously minimize the amount of
organic solvent released during subsequent formation and cure of
polyetherimide resins as in the manufacture of solvent cast film.
Such solutions having high amounts of monomeric reactants may have
higher viscosities than desired for some solvent cast films.
Typically, inclusion of water decreases the solution viscosity. A
given decrease in viscosity may be effected using a lower amount of
added water relative to the amount of added organic solvent
component which would be required to effect the same viscosity
decrease.
[0063] Water may or may not be a part of the polyamic acid
solution. Water may be present in any amount up to the maximum
amount at which the solution is substantially free of precipitate.
Although water is miscible with the organic solvent component in
substantially all proportions, inclusion of too much water in the
present monomeric solution results in precipitate or other plural
phase formation. The amount of water which may be present depends
on the particular dianhydride and diamine components, the
particular organic solvent component, and the weight ratio of
monomeric reactants to organic solvent.
[0064] Advantageously, the present polyamic acid solutions may
include the monomeric reactants in a combined amount of 40 or more
weight percent, e.g. from 40 to 75 or more weight percent, based on
the weight of the solution. In general, such high monomer content
solutions, including water as may be required, have suitable
viscosities in the temperature range, e.g., 15.degree. C. to
200.degree. C., normally used to make solvent cast films.
[0065] Solutions including water are more easily prepared by adding
the monomeric reactant components with stirring to a solution of
the water and organic solvent component. Preparation of the
solution is generally accelerated at elevated temperatures.
[0066] An additive can be added to the polyamic acid solutions in
order to reduce the CTE below the CTE that the material would have
without the additive. These additives include those which will aid
in lowering the CTE of the solvent cast film, and those which can
aid in producing another desirable property in the present films.
These ingredients may be used in any amount to impart the desired
property at proportions of from 0.001 to 60 parts of additive, per
100 parts by weight of polyimide. Alternatively these additives may
be added in amounts from 0.01 to 30 parts of additive, and more
particularly from 0.1 to 10 parts of additive per 100 parts by
weight of polyimide.
[0067] The types of additives which can be employed to lower the
CTE of a solvent cast polyimide film include modified
nano-composite silicates (nanoclays) and soluble nano-particle
precursors such as aluminum (acetylacetonoate).sub.3.
[0068] A nanoclay can be added directly to the polyamic acid
composition after it is formed. It has also been found that
polyimide can be readily solubilized in an exfoliated nanocomposite
solution, and that exfoliation can be maintained after removal of
the solvent by devolatization or precipitation into nonsolvent. The
resulting polyimide-nanocomposite materials can be formed into
films via solution casting or melt extrusion. The resulting films
have high Tg and low CTE.
[0069] Moreover, it has been found that polymerization of a diamine
and dianhydride in the presence of organically modified
nanosilicates results in good dispersion of the modified
nanofiller. The nanofilled polyimide composite can be formed into
films by melt extrusion or solution casting to give a low CTE, high
Tg, polyimide film.
[0070] Exfoliated nanoclays are most commonly used. Exfoliation,
e.g., by sonication, is carried out in a solvent system. For
example exfoliating is carried out in a composition comprising from
10 to 90% by weight of the nanoclay and from 10 to 90% by weight of
the solvent system. Exfoliation can be performed before addition to
the polyamic acid solution, after addition to the polyamic acid
solution, or before reacting the dianhydride component and the
organic diamine component in the solvent system. Alternatively,
addition of a high molecular weight polymer to the exfoliated
nanosilicate solution results in exfoliated high Tg nanocomposites.
These materials can be formed into films by solution casting to
give a low CTE polyimide film. In one embodiment homogenization of
the modified nanosilicate in the selected solvent is followed by
sonication. Sonication can be performed in either a batch or
continuous process. In the batch process, the homogenized modified
silicate/solvent mixture is placed in contact with the sonic
source. The mixture is stirred well to ensure uniform sonication of
the entire mixture. In the continuous process, the modified
nanosilicate/solvent mixture is flowed through the sonic zone at a
given rate. The modified nanosilicate/solvent mixture is stirred
well to ensure a uniform dispersion of the nanosilicate. In either
the batch or continuous process, the sonication conditions required
for exfoliation (i.e. flow rate, sonication power, sonication time)
depends on the type of modifier used, solvent, batch size,
configuration and size of the sonic source, and temperature at
which sonication takes place. Intercalation and exfoliation of the
nanosilicate particles can be observed via X-ray diffraction (XRD)
of the resulting solution. Exfoliation can be more directly
observed by combining the sonicated nanosilicate solution with a
polyimide solution, removing the solvent by evaporation or
precipitation, casting or pressing a film and performing TEM
analysis.
[0071] The nanosilicates may be exfoliated such that the materials
d-spacing is greater than the material would have, but for the
exfoliation step. According to the present invention the d-spacing
can be any that is greater than the unmodified nanosilicate that
will lower the CTE of the polyimide film. According to alternate
embodiments, the modified nanosilicates will have d-spacings
greater than 15, 20, 25, 30, 40, 50, and 75 Angstroms.
[0072] It has been found that use of nanoclays, particularly
exfoliated nanoclays provides unexpected advantages. Films
comprising a nanoclay can have a lower CTE than a film of the same
composition without the nanoclay. Alternatively, or in addition,
films comprising a nanoclay can have a Tg that is the same as a
film of the same composition without the nanoclay. A film
comprising a nanoclay can also be transparent. The amount of
nanoclay used in the film will vary, depending on the desired film
properties. For example, the film can comprise from 0.1 to 10 wt %
nanoclay, specifically 1 to 10 wt % nanoclay, based on the total
weight of the film.
[0073] The nanosilicate can have an organic modifier with cationic
functionality and may be thermally stable at film forming
processing temperatures.
[0074] A general methodology for making solvent cast films
according to this process involves dispersing the modified clay
either by sonication or high shear mixing in the chosen solvent
(for example, DMAc). The clay dispersion is formulated to be in the
range of 1-15% solids by weight, or more particularly, 1-5% solids
by weight. The monomers, at least one dianhydride monomer and at
least one diamine monomer, are added to the clay dispersion to form
a modified polyamic acid solution. Also, instead of adding polyamic
acid to the clay dispersion, fully imidized soluble polyimides can
be dissolved in solvents such as DMAc and NMP in the range of 5-25%
solids by weight, for example 10% by weight. In another embodiment,
a 10% by weight solution of the dried film in dimethylacetamide or
N-methylpyrolidinone has an inherent viscosity of greater than 0.05
dl/g. The polyimide solution can then be combined with the clay
dispersion and cast as above.
[0075] Another additive which can be employed to lower the CTE of
solvent cast polyimide films are metal oxide nanoparticles which
can be formed from an organo-metallic precursor. Metal oxide
nanoparticles can be generated in situ by decomposing an
organometallic precursor. One example of such a material is
aluminum(acetylacetonate).sub.3 (Al(acac).sub.3). Thermolysis of
(Al(acac).sub.3) yields aluminum oxide. When done in dilute
solution (small molecule solvent or polymer melt) Al.sub.2O.sub.3
nanoparticles are formed. Targeting a 1% by weight loading of
Al.sub.2O.sub.3 in the final polymer, the precursor can be added
upfront to the polymerization of dianhydride and diamine monomers,
specifically oxydiphthalic anhydride and diaminodiphenylsulfone.
Resultant polymer filled with Al.sub.2O.sub.3 nanoparticles
exhibited a CTE lowered by more than 15% compared to an unfilled
control sample.
[0076] In addition to the organo-metallic precursor being added to
the polymerization, the precursor can be solvent blended with the
polyamic acid solution, or finished soluble polyimide, or blended
and extruded with finished polymer to yield a filled system. The
materials in solution can be cast as films and cured to give the
filled film. Other suitable organo-metallic precursors include
metal(acac) complexes, and ceramic precursors such as molybdenum
sulfide.
[0077] Other classes of additives which can be used to impart a
desirable property other than, or in addition to lowering the CTE
of a polyimide film, include fillers and reinforcements for example
fiber glass, milled glass, glass beads, flake and the like.
Minerals such as talc, wollastonite, mica, kaolin, or
montmorillonite clay, silica, fumed silica, perlite, quartz, and
barite may be added. The compositions can also be modified with
effective amounts of inorganic fillers, such as, for example,
carbon fibers and nanotubes, glass fibers, metal fibers, metal
powders, conductive carbon, and other additives including
nano-scale reinforcements.
[0078] In some cases a metal oxide may be added to the polymers of
the present invention. In some instances the metal oxide may
further improve flame resistance (FR) performance by decreasing
heat release and increasing the time to peak heat release. Titanium
dioxide is of note. Other metal oxides include zinc oxides, boron
oxides, antimony oxides, iron oxides, and transition metal oxides.
Metal oxides that are white may be desired in some instances. Metal
oxides may be used alone or in combination with other metal oxides.
Metal oxides may be used in any effective amount, in some instances
at from 0.01 to 20% by weight of the polymer.
[0079] Other useful additives include smoke suppressants such as
metal borate salts, for example zinc borate, alkali metal or
alkaline earth metal borate or other borate salts. Additionally
other boron containing compounds, such as boric acid, borate
esters, boron oxides, or other oxygen compounds of boron may be
useful. Additionally other flame retardant additives, such as aryl
phosphates and brominated aromatic compounds, including polymers
containing linkages made from brominated aryl compounds, may be
employed. Examples of halogenated aromatic compounds are brominated
phenoxy resins, halogenated polystyrenes, halogenated imides,
brominated polycarbonates, brominated epoxy resins and mixtures
thereof.
[0080] In some instances it maybe desired to have flame retardant
compositions that are essentially free of halogen atoms, especially
bromine and chlorine. Essentially free of halogen atoms means that
in some embodiments the composition has less than 3% halogen,
specifically chlorine and/or bromine by weight of the composition,
and in other embodiments less than 1% by weight of the composition
contains halogen atoms, specifically chlorine and/or bromine. The
amount of halogen atoms can be determined by ordinary chemical
analysis.
[0081] The composition may also optionally include a fluoropolymer
in an amount of 0.01 to 5.0% fluoropolymer by weight of the
composition. The fluoropolymer may be used in any effective amount
to provide anti-drip properties to the resin composition. Some
examples of suitable fluoropolymers and methods for making such
fluoropolymers are set forth, for example, in U.S. Pat. Nos.
3,671,487, 3,723,373 and 3,383,092. Suitable fluoropolymers include
homopolymers and copolymers that comprise structural units derived
from one or more fluorinated alpha-olefin monomers. The term
"fluorinated alpha-olefin monomer" means an alpha-olefin monomer
that includes at least one fluorine atom substituent. Some of the
suitable fluorinated alpha-olefin monomers include, for example,
fluoroethylenes such as, for example, CF.sub.2.dbd.CF.sub.2,
CHF.dbd.CF.sub.2, CH.sub.2.dbd.CF.sub.2, and CH.sub.2.dbd.CHF and
fluoro propylenes such as, for example, CF.sub.3CF.dbd.CF.sub.2,
CF.sub.3CF.dbd.CHF, CF.sub.3CH.dbd.CF.sub.2,
CF.sub.3CH.dbd.CH.sub.2, CF.sub.3CF.dbd.CHF, CHF.sub.2CH.dbd.CHF,
and CF.sub.3CF.dbd.CH.sub.2.
[0082] Some of the suitable fluorinated alpha-olefin copolymers
include copolymers comprising structural units derived from two or
more fluorinated alpha-olefin monomers such as, for example,
poly(tetrafluoro ethylene-hexafluoro ethylene), and copolymers
comprising structural units derived from one or more fluorinated
monomers and one or more non-fluorinated monoethylenically
unsaturated monomers that are copolymerizable with the fluorinated
monomers such as, for example,
poly(tetrafluoroethylene-ethylene-propylene) copolymers. Suitable
non-fluorinated monoethylenically unsaturated monomers include for
example, alpha-olefin monomers such as, for example, ethylene,
propylene, butene, acrylate monomers such as for example, methyl
methacrylate, butyl acrylate, and the like, with
poly(tetrafluoroethylene) homopolymer (PTFE) preferred.
[0083] Other additives which may be added to the solvent cast films
include antioxidants such as phosphites, phosphonites, and hindered
phenols. Phosphorus containing stabilizers, including triaryl
phosphite and aryl phosphonates, are of note as useful additives.
Difunctional phosphorus containing compounds can also be employed.
Stabilizers with a molecular weight of 300 Daltons or more are
preferred. In other instances phosphorus containing stabilizers
with a molecular weight of greater than or equal to 500 Daltons are
useful. Phosphorus containing stabilizers are typically present in
the composition at 0.05-0.5% by weight of the formulation.
Colorants as well as light stabilizers and UV absorbers may also be
used. Flow aids and mold release compounds are also contemplated.
Examples of mold release agents are alkyl carboxylic acid esters,
for example, pentaerythritol tetrastearate, glycerin tri-stearate,
and ethylene glycol distearate. Mold release agents are typically
present in the composition at 0.05-0.5% by weight of the
formulation. Preferred mold release agents will have high molecular
weight, typically greater than 300 Daltons, to prevent loss if the
release agent from the molten polymer mixture during melt
processing.
[0084] Compositions used to form the articles according to the
present invention may also include various additives such as
nucleating, clarifying, stiffness, and/or crystallization rate
agents. These agents are used in a conventional matter and in
conventional amounts.
[0085] The compositions can be blended with the aforementioned
ingredients by a variety of methods involving intimate mixing of
the materials with any additional additives desired in the
formulation. A preferred procedure includes solution blending,
although melt blending may be employed after the solvent cast film
is made. Illustrative examples of equipment used in such melt
processing methods include co-rotating and counter-rotating
extruders, single screw extruders, co-kneaders, disc-pack
processors, and various other types of extrusion equipment.
[0086] Liquid coating solutions can be formed using the
above-described polyimide compositions, as well as film-forming
solutions. The liquid coating solutions have many and varied uses.
The coating solutions can be applied to a variety of substrates
using any suitable coating method, e.g. dipping, brushing,
spraying, wiping and the like, and thereafter heated to evaporate
the solvent system and form cured polyetherimide resinous coatings.
The temperature is preferably increased gradually to produce smooth
resinous coatings. The polymerization and cure proceeds
advantageously at a temperature of from 125.degree. C. to
300.degree. C. or more.
[0087] The polyamic acid solution can also be used as a coating
solution which may be applied immediately upon preparation or
stored prior to use. In general, maximum storage life can be
obtained by storing the solutions under a nitrogen blanket in the
absence of light.
[0088] Polymers used to make the solvent cast films and coatings
are polyimides and in some specific instances, polyetherimides.
Polyimides according to the present invention have the general
formula (1):
##STR00001##
wherein a is more than 1, typically 10 to 1,000 or more, or more
specifically 10 to 500; and wherein V is a tetravalent linker
without limitation, as long as the linker does not impede synthesis
or use of the polyimide. Suitable linkers include but are not
limited to: (a) substituted or unsubstituted, saturated,
unsaturated or aromatic monocyclic and polycyclic groups having 5
to 50 carbon atoms, (b) substituted or unsubstituted, linear or
branched, saturated or unsaturated alkyl groups having 1 to 30
carbon atoms; or combinations comprising at least one of the
foregoing. Suitable substitutions and/or linkers include, but are
not limited to, ethers, epoxides, amides, esters, and combinations
comprising at least one of the foregoing. At least a portion of the
linkers V contain a portion derived from a bisphenol. Desirably
linkers include but are not limited to tetravalent aromatic
radicals of structures (2):
##STR00002##
wherein W is a divalent moiety including --O--, --S--, --C(O)--,
--SO.sub.2--, --SO--, --C.sub.yH.sub.2y-- (y being an integer from
1 to 5), and halogenated derivatives thereof, including
perfluoroalkylene groups, or a group of the formula --O--Z--O--
wherein the divalent bonds of the --O-- or the --O--Z--O-- group
are in the 3,3', 3,4', 4,3', or the 4,4' positions, and wherein Z
includes, but is not limited, to divalent radicals of formulas
3:
##STR00003##
wherein Q includes but is not limited to a divalent moiety
including --O--, --S--, --C(O)--, --SO.sub.2--, --SO--,
--C.sub.yH.sub.2y-- (y being an integer from 1 to 5), and
halogenated derivatives thereof, including perfluoroalkylene
groups.
[0089] R in formula (1) includes but is not limited to substituted
or unsubstituted divalent organic radicals such as: (a) aromatic
hydrocarbon radicals having 6 to 20 carbon atoms and halogenated
derivatives thereof, (b) straight or branched chain alkylene
radicals having 2 to 20 carbon atoms; (c) cycloalkylene radicals
having 3 to 20 carbon atoms, or (d) divalent radicals of the
general formula (4):
##STR00004##
wherein Q includes but is not limited to a divalent moiety
including --O--, --S--, --C(O)--, --SO.sub.2--, --SO--,
--C.sub.yH.sub.2y-- (y being an integer from 1 to 5), and
halogenated derivatives thereof, including perfluoroalkylene
groups.
[0090] Exemplary classes of polyimides include polyamidimides and
polyetherimides, particularly those polyetherimides which are melt
processible, such as those whose preparation and properties are
described in U.S. Pat. Nos. 3,803,085 and 3,905,942.
[0091] Exemplary polyetherimide resins comprise more than 1,
typically 10 to 1,000, or more specifically, 10 to 500 structural
units, of the formula (5):
##STR00005##
wherein T is --O-- or a group of the formula --O--Z--O-- wherein
the divalent bonds of the --O-- or the --O--Z--O-- group are in the
3,3', 3,4', 4,3', or the 4,4' positions, and wherein Z includes,
but is not limited, to divalent radicals of formula 10 as defined
above.
[0092] In one embodiment, the polyetherimide may be a copolymer
which, in addition to the etherimide units described above, further
contains polyimide structural units of the formula (6):
##STR00006##
wherein R is as previously defined for formula (6) and M includes,
but is not limited to, radicals of the following formulas:
##STR00007##
[0093] The polyetherimide can be prepared by various methods,
including, but not limited to, the reaction of an aromatic
bis(ether anhydride) of the formula (7):
##STR00008##
with an organic diamine of the formula (8):
H.sub.2N--R--NH.sub.2 (8)
wherein R and T are defined in relation to formulas (1) and
(5).
[0094] Examples of specific aromatic bis(ether anhydride)s and
organic diamines are disclosed, for example, in U.S. Pat. Nos.
3,972,902 and 4,455,410. Illustrative examples of dianhydride
molecules include: [0095]
2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride; [0096]
4,4'-bis(3,4-dicarboxyphenoxy)diphenylether dianhydride; [0097]
4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfide dianhydride; [0098]
4,4'-bis(3,4-dicarboxyphenoxy)benzophenone dianhydride; [0099]
4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfone dianhydride; [0100]
2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride; [0101]
4,4'-bis(2,3-dicarboxyphenoxy)diphenylether dianhydride; [0102]
4,4'-bis(2,3-dicarboxyphenoxy)diphenylsulfide dianhydride; [0103]
4,4'-bis(2,3-dicarboxyphenoxy)benzophenone dianhydride; [0104]
4,4'-bis(2,3-dicarboxyphenoxy)diphenylsulfone dianhydride; [0105]
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenyl-2,2-propane
dianhydride; [0106]
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenylether
dianhydride; [0107]
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenylsulfide
dianhydride; [0108]
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)benzophenone
dianhydride; [0109]
4-(2,3-dicarboxyphenoxy)-4'-(3,4-dicarboxyphenoxy)diphenylsulfone
dianhydride; [0110] 1,3-bis(2,3-dicarboxyphenoxy)benzene
dianhydride; [0111] 1,4-bis(2,3-dicarboxyphenoxy)benzene
dianhydride; [0112] 1,3-bis(3,4-dicarboxyphenoxy)benzene
dianhydride; [0113] 1,4-bis(3,4-dicarboxyphenoxy)benzene
dianhydride; [0114] 3,3',4,4'-diphenyl tetracarboxylic dianhydride;
[0115] 3,3',4,4'-benzophenonetetracarboxylic dianhydride; [0116]
naphthalic dianhydrides, such as 2,3,6,7-naphthalic dianhydride,
etc.; [0117] 3,3',4,4'-biphenylsulphonictetracarboxylic
dianhydride; [0118] 3,3',4,4'-biphenylethertetracarboxylic
dianhydride; [0119] 3,3',4,4'-dimethyldiphenylsilanetetracarboxylic
dianhydride; [0120] 4,4'-bis (3,4-dicarboxyphenoxy)diphenylsulfide
dianhydride; [0121] 4,4'-bis (3,4-dicarboxyphenoxy)diphenylsulphone
dianhydride; [0122] 4,4'-bis (3,4-dicarboxyphenoxy)diphenylpropane
dianhydride; [0123] 3,3',4,4'-biphenyltetracarboxylic dianhydride;
[0124] bis(phthalic)phenylsulphineoxide dianhydride; [0125]
p-phenylene-bis(triphenylphthalic) dianhydride; [0126]
m-phenylene-bis(triphenylphthalic) dianhydride; [0127]
bis(triphenylphthalic)-4,4'-diphenylether dianhydride; [0128]
bis(triphenylphthalic)-4,4'-diphenylmethane dianhydride; [0129]
2,2'-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride; [0130]
4,4'-oxydiphthalic dianhydride; [0131] pyromellitic dianhydride;
[0132] 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride; [0133]
4',4'-bisphenol A dianhydride; [0134] hydroquinone diphthalic
dianhydride; [0135]
6,6'-bis(3,4-dicarboxyphenoxy)-2,2',3,3'-tetrahydro-3,3,3',3'-tetramethyl-
-1,1'-spirobi[1H-indene]dianhydride; [0136]
7,7'-bis(3,4-dicarboxyphenoxy)-3,3',4,4'-tetrahydro-4,4,4',4'-tetramethyl-
-2,2'-spirobi[2H-1-benzopyran]dianhydride; [0137]
1,1'-bis[1-(3,4-dicarboxyphenoxy)-2-methyl-4-phenyl]cyclohexane
dianhydride; [0138] 3,3',4,4'-diphenylsulfonetetracarboxylic
dianhydride; [0139] 3,3',4,4'-diphenylsulfidetetracarboxylic
dianhydride; [0140] 3,3',4,4'-diphenylsulfoxidetetracarboxylic
dianhydride; [0141] 4,4'-oxydiphthalic dianhydride; [0142]
3,4'-oxydiphthalic dianhydride; [0143] 3,3'-oxydiphthalic
dianhydride; [0144] 3,3'-benzophenonetetracarboxylic dianhydride;
[0145] 4,4'-carbonyldiphthalic dianhydride; [0146]
3,3',4,4'-diphenylmethanetetracarboxylic dianhydride; [0147]
2,2-bis(4-(3,3-dicarboxyphenyl)propane dianhydride; [0148]
2,2-bis(4-(3,3-dicarboxyphenyl)hexafluoropropane dianhydride;
[0149] (3,3',4,4'-diphenyl)phenylphosphinetetracarboxylic
dianhydride; [0150]
(3,3',4,4'-diphenyl)phenylphosphineoxidetetracarboxylic
dianhydride; [0151] 2,2'-dichloro-3,3',4,4'-biphenyltetracarboxylic
dianhydride; [0152] 2,2'-dimethyl-3,3',4,4'-biphenyltetracarboxylic
dianhydride; [0153] 2,2'-dicyano-3,3',4,4'-biphenyltetracarboxylic
dianhydride; [0154] 2,2'-dibromo-3,3',4,4'-biphenyltetracarboxylic
dianhydride; [0155] 2,2'-diiodo-3,3',4,4'-biphenyltetracarboxylic
dianhydride; [0156]
2,2'-trifluoromethyl-3,3',4,4'-biphenyltetracarboxylic dianhydride;
[0157]
2,2'-bis(1-methyl-4-phenyl)-3,3',4,4'-biphenyltetracarboxylic
dianhydride; [0158]
2,2'-bis(1-trifluoromethyl-2-phenyl)-3,3',4,4'-biphenyltetracarboxylic
dianhydride; [0159]
2,2'-bis(1-trifluoromethyl-3-phenyl)-3,3',4,4'-biphenyltetracarboxylic
dianhydride; [0160]
2,2'-bis(1-trifluoromethyl-4-phenyl)-3,3',4,4'-biphenyltetracarboxylic
dianhydride; [0161]
2,2'-bis(1-phenyl-4-phenyl)-3,3',4,4'-biphenyltetracarboxylic
dianhydride; [0162] 4,4'-bisphenol A dianhydride; [0163]
3,3',4,4'-diphenylsulfoxidetetracarboxylic dianhydride; [0164]
4,4'-carbonyldiphthalic dianhydride; [0165]
3,3',4,4'-diphenylmethanetetracarboxylic dianhydride; [0166]
2,2'-bis(1,3-trifluoromethyl-4-phenyl)-3,3',4,4'-biphenyltetracarboxylic
dianhydride, and all isomers thereof, as well as a combination of
the foregoing.
[0167] The bis(ether anhydride)s can be prepared by the hydrolysis,
followed by dehydration, of the reaction product of a nitro
substituted phenyl dinitrile with a metal salt of a bisphenol
compound (e.g., BPA) in the presence of a dipolar, aprotic solvent.
An exemplary class of aromatic bis(ether anhydride)s included by
formula (7) above includes, but is not limited to, compounds
wherein T is of the formula (9):
##STR00009##
and the ether linkages, for example, are in the 3,3', 3,4', 4,3',
or 4,4' positions, and mixtures comprising at least one of the
foregoing, and where Q is as defined above.
[0168] Any diamino compound may be employed. Examples of suitable
compounds are: [0169] m-phenylenediamine; [0170]
p-phenylenediamine; [0171] 2,4-diaminotoluene; [0172]
2,6-diaminotoluene; [0173] m-xylylenediamine; [0174]
p-xylylenediamine; [0175] benzidine; [0176] 3,3'-dimethylbenzidine;
[0177] 3,3'-dimethoxybenzidine; [0178] 1,5-diaminonaphthalene;
[0179] bis(4-aminophenyl)methane; [0180] bis(4-aminophenyl)propane;
[0181] bis(4-aminophenyl)sulfide; [0182] bis(4-aminophenyl)sulfone;
[0183] bis(4-aminophenyl)ether; [0184] 4,4'-diaminodiphenylpropane;
[0185] 4,4'-diaminodiphenylmethane(4,4'-methylenedianiline); [0186]
4,4'-diaminodiphenylsulfide; [0187] 4,4'-diaminodiphenylsulfone;
[0188] 4,4'-diaminodiphenylether(4,4'-oxydianiline); [0189]
1,5-diaminonaphthalene; [0190] 3,3'dimethylbenzidine; [0191]
3-methylheptamethylenediamine; [0192]
4,4-dimethylheptamethylenediamine; [0193]
2,2',3,3'-tetrahydro-3,3,3',3'-tetramethyl-1,1'-spirobi[1H-indene]-
-6,6'-diamine; [0194]
3,3',4,4'-tetrahydro-4,4,4',4'-tetramethyl-2,2'-spirobi[2H-1-benzopyran]--
7,7'-diamine; [0195]
1,1'-bis[1-amino-2-methyl-4-phenyl]cyclohexane, and isomers thereof
as well as mixtures and blends comprising at least one of the
foregoing.
[0196] Desirably, the diamino compounds are aromatic diamines,
especially m- and p-phenylenediamine and mixtures comprising at
least one of the foregoing.
[0197] In one embodiment, the polyetherimide resin comprises
structural units according to formula 12 wherein each R is
independently p-phenylene or m-phenylene or a mixture comprising at
least one of the foregoing and T is a divalent radical of the
formula (10):
##STR00010##
[0198] Included among the many methods of making the polyimides,
particularly polyetherimides, are those disclosed in U.S. Pat. Nos.
3,847,867, 3,850,885, 3,852,242, 3,855,178, 3,983,093, and
4,443,591.
[0199] The reactions can be carried out employing solvents, e.g.,
o-dichlorobenzene, m-cresol/toluene and the like, to effect a
reaction between the anhydride of formula (7) and the diamine of
formula (8), at temperatures of 100.degree. C. to 250.degree. C.
Chain stoppers and branching agents may also be employed in the
reaction.
[0200] When polyimide copolymers of ether-containing and non-ether
containing subunits are used, a dianhydride, such as pyromellitic
anhydride, is used in combination with the bis(ether anhydride).
The polyimides can optionally be prepared from reaction of an
aromatic bis(ether anhydride) with an organic diamine in which the
diamine is present in the reaction mixture at less than or equal to
0.2 molar excess. Under such conditions the polyetherimide resin
may have less than or equal to 15 microequivalents per gram
(.mu.eq/g) acid titratable groups, or, more specifically less than
or equal to 10 microequivalents/g acid titratable groups, as shown
by titration with chloroform solution with a solution of 33 weight
percent (wt %) hydrobromic acid in glacial acetic acid.
Acid-titratable groups are essentially due to amine end-groups in
the polyetherimide resin.
[0201] One route for the synthesis of polyimides proceeds through a
bis(4-halophthalimide) having the following structure (11):
##STR00011##
wherein R is as described above and X is a halogen. The
bis(4-halophthalimide) wherein R is a 1,3-phenyl group (12) is
particularly useful.
##STR00012##
[0202] Bis(halophthalimide)s (11) and (12) are typically formed by
the condensation of amines, e.g., 1,3-diaminobenzene with
anhydrides, e.g., 4-halophthalic anhydride (13):
##STR00013##
[0203] Polyetherimides may be synthesized by the reaction of the
bis(halophthalimide) with an alkali metal salt of a bisphenol such
as bisphenol A or a combination of an alkali metal salt of a
bisphenol and an alkali metal salt of another dihydroxy substituted
aromatic hydrocarbon in the presence or absence of phase transfer
catalyst. Suitable phase transfer catalysts are disclosed in U.S.
Pat. No. 5,229,482. Suitable dihydroxy substituted aromatic
hydrocarbons include those having the formula (14):
OH-A.sup.2-OH (14) [0204] wherein A.sup.2 is a divalent aromatic
hydrocarbon radical. Suitable A.sup.2 radicals include m-phenylene,
p-phenylene, 4,4'-biphenylene, and similar radicals.
[0205] As described above, virgin polyimides can be used in the
formation of the solvent cast polyimide films. However, in a
specific embodiment, the polyimide films comprise up to 50 wt %,
specifically up to 30 wt %, of a recycled polyimide. The recycled
polyimide, prior to recycling, can have a glass transition
temperature from 210.degree. C. to 450.degree. C. In one
embodiment, virgin polyimide is melt blended with recycled
polyimide, for example polyimide that has already been formed into
a film as described above. In another embodiment, virgin polyimide
is solvent mixed with recycled polyimide, for example polyimide
that has been formed into a film as described above. Polyimide
compositions comprising the recycled polyimide can then be formed
into a casting composition and be cast as described above, for
example from a composition comprising 1 to 30 wt % solids. In the
foregoing embodiments, the CTE of the film comprising the recycled
polyimide can be within .+-.10 ppm/.degree. C. of a film having the
same composition without the recycled polyimide.
[0206] The above described solvent cast polyimide films can be used
to manufacture recycled compositions for a variety of uses. The
recycled compositions can be formed by melt bending (when the
recycled film is capable of being melt blended) or by solvent
mixing. In one embodiment, a method for the manufacture of recycled
polyimide composition comprises melting the solvent cast polyimide
film as described herein; and combining the melted solvent cast
polyimide film of claim 1 with a polymer composition to form a
recycled a polyimide composition. In another embodiment, a method
of manufacture of a recycled a polyimide composition comprises
dissolving the solvent cast polyimide film and combining the
dissolved film of claim 1 with a polymer composition to form the
recycled polyimide composition. In either of the foregoing
embodiments, the polymer composition can comprise a virgin
polyimide. The recycled compositions can then be used in the
manufacture of compositions and articles as is known in the art.
For example, the recycled polyimide composition can be extruded, or
cast as described above. Articles comprising the recycled polyimide
compositions are within the scope of the invention.
[0207] As an alternative to creating a solvent cast film having a
CTE less than 70 ppm/.degree. C., in another embodiment less than
60 ppm/.degree. C., or in another embodiment, less than 35
ppm/.degree. C., it is possible to add an additional process step
to lower the CTE of a solvent cast film having a CTE above 70
ppm/.degree. C., above 60 ppm/.degree. C., or in another
embodiment, above 35 ppm/.degree. C., to a CTE below 60
ppm/.degree. C. and in another embodiment less than 35 ppm/.degree.
C., specifically less than 30 ppm/.degree. C.
[0208] The CTE of a solvent cast film can be reduced by biaxially
stretching as described in U.S. Pat. No. 5,460,890. Similarly, the
CTE of a melt extruded film or fully imidized solvent cast film can
be reduced by thermally biaxially stretching as described in U.S.
Pat. No. 5,260,407. The skilled artisan will be familiar with the
other known methods of lowering the CTE of a polyimide film.
[0209] For example, a film with a low in-plane CTE may be obtained
from polyimide resin compositions because the resin exhibits a
partial crystallinity after annealing, and the crystalline phases
can be aligned in two dimensions through biaxial stretching after
extrusion. The film can then be heat set while constrained in a
frame, returning the amorphous portion of the film back to a random
unoriented configuration while retaining the alignment of the
crystalline phases (and also inducing more aligned crystalline
domains). The alignment of the crystalline phases results in a film
with a low CTE. Since the amorphous part of the material is
returned to its random state the film will not exhibit shrinkage,
even when taken above the Tg of the material. This can lead to a
dimensionally stable film at flex fabrication temperatures, because
the crystalline domains are stable to temperatures above
400.degree. C. The film has high temperature survivability due to
the high Tg of the material and the partial crystallinity. The Tg
of the material is above the temperature of the solder float test,
which makes the material survive this test as well. The polymer
crystals do not melt until temperatures exceeding 400.degree. C.,
which is well above the temperatures seen during flex fabrication.
The crystals act as effective crosslinks below Tm, holding the
material together for high temperature survivability. The
crystallization kinetics of the composition identified below is
fairly slow, allowing the material to be melt extruded to a film
before significant crystallization takes place. The film can then
be heat set above Tg to induce crystallinity.
[0210] Very good film properties are obtained when a specific
combination of dianhydrides are used, especially when the specific
dianhydrides are used in combination with specific diamines. In one
embodiment, the dianhydrides comprise 3,4'-oxydiphthalic anhydride,
3,3'-oxydiphthalic anhydride, 4,4'-oxydiphthalic anhydride, and
combinations thereof. Other, additional dianhydrides can be present
to adjust the properties of the films. In one embodiment, however,
the polyimide has less than 15 molar % of structural units derived
from a member of the group consisting of biphenyltetracarboxylic
acid, a dianhydride of biphenyltetracarboxylic acid, an ester of
biphenyltetracarboxylic acid, and combinations thereof.
[0211] Alternatively, the polyimides are formed from a dianhydride
component that consists essentially of 3,4'-oxydiphthalic
anhydride, 3,3'-oxydiphthalic anhydride, 4,4'-oxydiphthalic
anhydride, and combinations thereof. In still another embodiment,
the polyimides are formed from a dianhydride component that
consists of 3,4'-oxydiphthalic anhydride, 3,3'-oxydiphthalic
anhydride, 4,4'-oxydiphthalic anhydride, and combinations
thereof.
[0212] It has further been found films having excellent properties
are obtained when the diamine component further comprises
m-phenylenediamine, p-phenylenediamine, 4,4'-oxydianiline,
1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, and
combinations thereof. In one embodiment, the diamine component
consists essentially of 4,4'-diaminodiphenyl sulfone,
m-phenylenediamine, p-phenylenediamine, 4,4'-oxydianiline,
1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, and
combinations thereof. In another embodiment, the diamine component
consists of 4,4'-diaminodiphenyl sulfone, m-phenylenediamine,
p-phenylenediamine, 4,4'-oxydianiline,
1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, and
combinations thereof, and no other diamines are present.
[0213] The polyimides are further advantageously formed from
structural units wherein the diamine component comprises greater
than or equal to 10 mole % of 4,4'-diaminodiphenyl sulfone, based
on the total moles of diamine component. In one embodiment the
diamine component comprises 10 to 100 mole % of
4,4'-diaminodiphenyl sulfone.
[0214] The films can have a number of advantageous properties, in
addition to low CTE, useful Tg, and low solvent retention. In one
embodiment, the film is stable, that is, loses less than 5% of its
initial weight after storage in water for 24 hours at 25.degree.
C., specifically less than 2% of its initial weight after storage
in water for 24 hours at 25.degree. C.
[0215] The liquid coating solutions, film casting solutions,
coatings, and solvent cast films of the present invention have many
and varied uses. The coating solutions may be applied to a variety
of substrates using any suitable coating method, e.g. dipping,
brushing, spraying, wiping and the like, and thereafter heated to
evaporate the solvent system and form cured polyimide resinous
coatings and/or solvent cast films. The temperature is preferably
increased gradually to produce smooth resinous coatings. The
polyimide-forming reaction proceeds advantageously at a temperature
of from 125.degree. C. to 450.degree. C. or more.
[0216] The present coating and casting solutions, including
compositions comprising a recycled polyimide film, may be employed
to manufacture a variety of articles comprising the solvent cast
polyimide films. In one embodiment, the film is disposed on a
substrate. A variety of substrates can be used, for example copper,
silicon, aluminum, gold, silver, nickel, a glass, a ceramic, and a
polymer, including a polymeric release layer. In one embodiment,
the substrate is a solvent cast polyimide film comprising
structural units derived from polymerization of a dianhydride
component comprising a dianhydride selected from the group
consisting of 3,4'-oxydiphthalic dianhydride, 3,3'-oxydiphthalic
dianhydride, 4,4'-oxydiphthalic dianhydride, and combinations
thereof, with a diamine component; wherein the polyimide has a
glass transition temperature of at least 190.degree. C.; wherein
the film has a coefficient of thermal expansion of less than 60
ppm/.degree. C., a thickness from 0.1 to 250 micrometers, endless
than 5% residual solvent by weight; wherein the polyimide has less
than 15 molar % of structural units derived from a member selected
from the group consisting of biphenyltetracarboxylic acid, a
dianhydride of biphenyltetracarboxylic acid, an ester of
biphenyltetracarboxylic acid, and a combination thereof. A first
and a second substrate having the same or different compositions
can be disposed on opposite sides of the solvent cast film.
[0217] In one embodiment, the coating and casting solutions is used
to manufacture a laminate comprising the solvent cast polyimide
film, a conductive layer comprising a metal, wherein a side of the
film is adheringly disposed on a side of the conductive layer. The
conductive metal can be copper, silver, gold, aluminum, or an alloy
comprising at least one of the foregoing metals. In a specific
embodiment, the metal is copper and wherein the solvent cast film
has a coefficient of thermal expansion less than 35 ppm/.degree.
C.
[0218] In another embodiment, films for circuit boards, including
flexible circuit boards. In this embodiment, a solvent cast
polyetherimide film is adheringly disposed on an electrically
conductive substrate, for example a face of a metal layer such as
copper, wherein the metal is etched to provide a circuit. A second
substrate, e.g., another layer of a conductive material, i.e., a
metal such as copper, can be disposed on a side of the film
opposite the first substrate. The flexible printed circuit can
further comprise a dielectric layer comprising a second dielectric
material other than the polyimide of the film.
[0219] Other specific articles that can be manufactured using the
solvent cast polyimide films include capacitors, which in their
simplest embodiment comprise a solvent cast polyimide film
adheringly disposed between two electrically conductive layers,
e.g., two copper layers.
[0220] In still another embodiment, the solutions can be used as
wire enamels to form resinous insulating coatings on copper and
aluminum wire. In this embodiment, the polyimide film forms a
coating on an electrically conductive wire that surrounds at least
a portion of the radial surface of the wire.
[0221] The solutions can also be used as varnishes for coating or
impregnating various substrates such as coils of previously
insulated wire (e.g. in motor and generator coils), as well as
woven and non-woven fabrics, and the like. The solvent cast films
of the present invention may also be used for chip-on-flex (COF),
and tape automated bonding (TAB) applications. The term "articles"
can also include speaker cones, tapes and labels, wire wraps,
etc.
EXAMPLES
[0222] Without further elaboration, it is believed that the skilled
artisan can, using the description herein, make and use the present
invention. The following examples are included to provide
additional guidance to those skilled in the art of practicing the
claimed invention. These examples are provided as representative of
the work and contribute to the teaching of the present invention.
Accordingly, these examples are not intended to limit the scope of
the present invention in any way. Unless otherwise specified below,
all parts are by weight and all temperatures are in degrees
Celsius.
Materials
[0223] ODPA is a dianhydride monomer also known as
4,4'-oxydiphthalic anhydride which can be made as described in U.S.
Pat. No. 6,028,203, U.S. Pat. No. 4,870,194, or U.S. Pat. No.
5,021,168.
[0224] BPDA is a dianhydride monomer also known as
3,3',4,4'-biphenyltetracarboxylic dianhydride which is commercially
available from Chriskev Company, with offices in Leawood, Kans.
[0225] PMDA is a dianhydride monomer also known as pyromellitic
dianhydride, which is commercially available from Aldrich Chemical
Company, with offices in Milwaukee, Wisc.
[0226] BPADA is a dianhydride monomer also known as
2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, which
is commercially available from Aldrich Chemical Company, with
offices in Milwaukee, Wisc.
[0227] BTDA is a dianhydride monomer also known as
3,3'-benzophenonetetracarboxylic dianhydride which is commercially
available from TCI America, with offices in Portland, Oreg.
[0228] BPhDA is a dianhydride monomer also known as
4,4'-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride which can be
made as described in the Journal of Polymer Science, Polymer
Chemistry Edition, 1985, vol. 23(6), pp 1759-1769.
[0229] DDS is a diamine monomer also known as
4,4'-diaminodiphenylsulfone, which is commercially available from
Chriskev Company, with offices in Leawood, Kans.
[0230] MPD is a diamine monomer also known as
meta-phenylenediamine, which is commercially available from Aldrich
Chemical Company, with offices in Milwaukee, Wisc.
[0231] PPD is a diamine monomer also known as
para-phenylenediamine, which is commercially available from Aldrich
Chemical Company, with offices in Milwaukee, Wisc.
[0232] ODA is a diamine monomer also known as 4,4'-oxydianiline,
which is commercially available from Chriskev Company, with offices
in Leawood, Kans.
[0233] 1,3,4-APB is a diamine monomer also known as
1,3-bis(4-aminophenoxy)benzene, which is commercially available
from Chriskev Company, with offices in Leawood, Kans.
[0234] 1,3,3-APB is a diamine monomer also known as
1,3-bis(3-aminophenoxy)benzene, which is commercially available
from Chriskev Company, with offices in Leawood, Kans.
[0235] TPPBr is a phosphonium salt also known as
tetraphenylphosphonium bromide, which is commercially available
from Fluorochem Ltd., with offices in Old Glossop, United
Kingdom.
[0236] Sodium montmorillonite is an inorganic layered silicate,
which is commercially available from Sud-Chemie, with offices in
Dusseldorf, Germany.
Examples 1-43
Film Casting Procedure and Experimental for Examples 1-43:
[0237] Inventive formulations 1-43 were prepared using the
compositions specified in Table 1. The amounts of each monomer were
calculated at a stoichiometry of 1 amine for every anhydride with
no correction for purity, (corrections for purity can effect the
final molecular weight of the polymer and could effect the final
performance of the article). A Microsoft Excel spreadsheet
calculator was constructed that calculates the grams of each
monomer based upon the total grams polymer desired and the monomer
feeds of dianhydride and amine. The skilled artisan will appreciate
that there are many different ways of ascertaining the correct
amount by weight of each ingredient to be used in making the films
according to the present invention. It is within the ability of the
skilled artisan to calculate the weight amount of ingredients based
on the overall stoichiometry and the final percent solids of the
reaction mechanism enunciated herein.
[0238] Casting Procedure: The correct molar percentages of
dianhydride and diamine as shown in Table 1 were weighed on an
analytical balance to four decimal place accuracy.
TABLE-US-00001 TABLE 1 Dianhydrides Diamines ODPA BPDA BTDA BPhDA
PMDA BPADA DDS PPD 133APB 134APB MPD ODA Ex. Solvent (%) (%) (%)
(%) (%) (%) (%) (%) (%) (%) (%) (%) 1 DMAc 50 0 0 0 0 0 50 0 0 0 0
0 2 NMP/CH 40 10 0 0 0 0 50 0 0 0 0 0 3 NMP/CH 10 40 0 0 0 0 50 0 0
0 0 0 4 NMP/CH 40 10 0 0 0 0 50 0 0 0 0 0 5 NMP/CH 10 40 0 0 0 0 50
0 0 0 0 0 6 NMP/CH 40 10 0 0 0 0 40 10 0 0 0 0 7 NMP/CH 40 10 0 0 0
0 10 40 0 0 0 0 8 NMP/CH 10 40 0 0 0 0 40 10 0 0 0 0 9 NMP/CH 10 40
0 0 0 0 10 40 0 0 0 0 10 DMAc 45 0 5 0 0 0 50 0 0 0 0 0 11 DMAc 5 0
45 0 0 0 50 0 0 0 0 0 12 DMAc 40 10 0 0 0 0 50 0 0 0 0 0 13 DMAc 10
40 0 0 0 0 50 0 0 0 0 0 14 DMAc 40 10 0 0 0 0 40 10 0 0 0 0 15 DMAc
40 10 0 0 0 0 10 40 0 0 0 0 16 DMAc 10 40 0 0 0 0 40 10 0 0 0 0 17
DMAc 10 40 0 0 0 0 10 40 0 0 0 0 18 DMAc 45 0 0 5 0 0 50 0 0 0 0 0
19 DMAc 0 45 0 5 0 0 50 0 0 0 0 0 20 DMAc 50 0 0 0 0 0 50 0 0 0 0 0
21 DMAc 50 0 0 0 0 0 40 0 0 0 10 0 22 DMAc 50 0 0 0 0 0 40 10 0 0 0
0 23 DMAc 50 0 0 0 0 0 40 0 0 0 0 10 24 DMAc 50 0 0 0 0 0 10 0 0 0
40 0 25 NMP 45 0 0 5 0 0 50 0 0 0 0 0 26 NMP 0 45 0 5 0 0 50 0 0 0
0 0 27 NMP 0 0 0 5 45 0 50 0 0 0 0 0 28 NMP 0 0 45 5 0 0 50 0 0 0 0
0 29 DMAc 50 0 0 0 0 0 10 40 0 0 0 0 30 DMAc 50 0 0 0 0 0 10 0 0 0
0 40 31 DMAc 10 40 0 0 0 0 50 0 0 0 0 0 32 DMAc 10 40 0 0 0 0 0 50
0 0 0 0 33 DMAc 10 40 0 0 0 0 40 0 0 0 10 0 34 DMAc 10 40 0 0 0 0
40 10 0 0 0 0 35 DMAc 10 40 0 0 0 0 40 0 0 0 0 10 36 DMAc 10 40 0 0
0 0 10 0 0 0 40 0 37 DMAc 10 40 0 0 0 0 10 40 0 0 0 0 38 DMAc 10 40
0 0 0 0 10 40 0 0 0 0 39 DMAc 50 0 0 0 0 0 40 0 0 10 0 0 40 DMAc 50
0 0 0 0 0 10 0 0 40 0 0 41 DMAc 40 10 0 0 0 0 10 40 0 0 0 0 42 DMAc
40 10 0 0 0 0 10 0 0 0 0 40 43 DMAc 10 40 0 0 0 0 0 10 0 40 0 0 CH
= cyclohexanone
[0239] The monomers were then transferred to a scintillation vial
and the weigh paper used was rinsed with the solvent. The remaining
volume of solvent was transferred to the vial and the vial was
rendered inert with nitrogen. The sealed inert vial was then placed
on a shaker overnight to produce a poly(amic acid) solution. The
poly(amic acid) solution was then drop cast through a 0.45
micrometer filter onto clean glass slides, prepared in advance by
cleaning with hexanes.
[0240] The coated slides were then placed on a hotplate equipped
with: a thermocouple; a ramp and soak temperature controller; a
nitrogen purge; and, a cover. The films were then imidized
following the heating profile outlined in Table 2 and FIG. 1:
TABLE-US-00002 TABLE 2 temp (.degree. C.) time (min) 25 0 40 45 40
60 120 90 120 120 160 150 160 165 200 180 200 195 300 210
[0241] Upon completion of the imidization reaction, the films so
produced were removed from the glass slide for use in later
examples, or for thorough property testing.
TABLE-US-00003 TABLE 3 Equilib Moisture CTE Tg Solubility**** Metal
moisture absorption Example (ppm/.degree. C.) (.degree. C.) DMAc
NMP Adhesion (%) (%) 1 42 318*** 2 45* 349 1.6 4.3 3 43* 325*** 6
44* 285 8 47* 327 9 43* 315 10 45 314 + + 3 11 50 327 12 45 + + 13
43 14 26 320 + + 4 0.3 1.9 15 23 - - 2 0.2 0.9 16 9 320 17 43 349
18 41*/44 1 2.2 19 40*/41 20 47** 319 + + 5 1.5 3.3 21 48** 22 47**
23 48** 24 43** 28 43 31 41 32 10 33 38 34 41 35 42 36 36 37 16 39
43 40 48 41 21 ND 43 44 *CTE Measured from 30-150.degree. C. **CTE
Measured from 30-175.degree. C. ***Tg determined by DMA ND no Tg
detected by DSC ****A + indicates at 10 wt % solids the cured film
dissolves. A - indicates that at 10 wt % solids the film did not
completely dissolve.
[0242] Weight % (wt %) is defined as: [weight of component/(weight
of component+weight of all other components)].times.100. Because
the initial curing profile was not optimum for every
formulation/solvent combination, some of the films were not
suitable for testing described in Table 3 and thus not represented.
It should be recognized by those skilled in the art that a suitable
combination of solvent and thermal processing profile might be
developed to make films that can be tested.
Example 44
Detailed Film Casting Example:
[0243] On an analytical balance, 0.5937 g (0.001914 mol) of
4,4'-oxydiphthalic anhydride and 0.4752 g (0.001914 mol) of
4,4'-diaminodiphenylsulfone were weighed out to be with in 0.0005 g
of the desired weight. The monomers were transferred to a 20 mL
scintillation vial, rinsing the weigh paper with 2.0 mL of
dimethylacetamide, to ensure complete transfer of the monomers. The
remaining solvent (5.47 mL of dimethylacetamide) was transferred by
volumetric pipette to give a solution of 12.5 weight % solids. The
vial was rendered inert by flowing nitrogen through the vial for
one minute and then quickly capping the vial. The sample was then
placed on the shaker overnight to form a poly(amic acid)
solution.
[0244] Glass slides (Fisherbrand precleaned microscope slides) were
cleaned with hexanes. The solution (2.0 mL) was then filtered
through a 0.45 micrometer syringe tip filter onto a glass slide.
The solution coated glass slide was then placed on a hotplate
equipped with a ramp and soak temperature controller, a cover, and
a controlled nitrogen purge of 85 liters (3 cubic feet) per hour
(apparatus volume of 0.1 cubic feet). The sample was then imidized
using the thermal profile outline described above for examples 1-8
and detailed in Tables 3 and FIG. 1. Following imidization the film
was released from the glass slide by immersion in water at
25.degree. C., to yield a freestanding polyimide film. The film was
then used for later examples or submitted for testing and
analysis.
Example 45
Detailed Film Casting Example:
[0245] On an analytical balance, 0.7559 g of 4,4'-oxydiphthalic
anhydride and 0.1210 g of diaminodiphenylsulfone and 0.2108 g of
para-phenylene diamine were weighed out to be with in 0.0005 g of
the desired weight. The monomers were transferred to a 20 mL
scintillation vial, rinsing the weigh paper with 1.0 mL of
dimethylacetamide, to ensure complete transfer of the monomers. The
remaining solvent (5.47 mL of dimethylacetamide) was transferred by
volumetric pipette to give a solution of 12.5 weight % solids. The
vial was rendered inert by flowing nitrogen through the vial for
one minute and then quickly capping the vial. The sample was then
placed on the shaker overnight to form a poly(amic acid)
solution.
[0246] Glass slides (Fisherbrand precleaned microscope slides) were
cleaned with hexanes. The solution (2.0 mL) was then filtered
through a 0.45-micrometer syringe tip filter onto a glass slide.
After the solution was filtered onto the slide a 635-micrometer
doctor blade (25 mil gap) was used to yield a wet film. (final film
thickness is a function of concentration and gap on the doctor
blade).
[0247] The solution coated glass slide was then placed on a
hotplate equipped with a ramp and soak temperature controller, a
cover, and a controlled nitrogen purge of 85 liters (3 cubic feet)
per hour (apparatus volume of 0.1 cubic feet). The sample was then
imidized using the thermal profile outline described above for
examples 1-43 and detailed in Tables 2 and FIG. 1. Following
imidization the film was released from the glass slide by immersion
in water at 25.degree. C., to yield a freestanding polyimide film.
The film was then used for later examples or submitted for testing
and analysis.
Example 46
[0248] Additional examples were performed with the following terms
being defined:
[0249] DSC: Differential Scanning Calorimetry was conducted on a
Perkin Elmer DSC 7 with a heating rate of 20.degree. C./min and the
glass transition measured in the second heat. This method is based
upon ASTM D3418.
[0250] DMA: Film samples cut precisely to give known length width
and thickness were analyzed on a dynamic mechanical analyzer in a
tensile mode with a frequency of 1 Hz and heating rate of 5.degree.
C./min over the temperature range 40-350.degree. C. Dynamic
mechanical analysis (DMA) is conducted in accordance to ASTM test
D5026, with the exception that only one test specimen is tested.
The glass transition temperature (Tg) is determined by the maximum
point of the tan delta curve.
[0251] TMA: CTE values of the cast films were measured on a
thermo-mechanical analyzer with a heating rate of 5.degree. C./min
from 0-250.degree. C. CTE values were calculated from the slope
over the range of 30-200.degree. C.
[0252] Equilibrium water: The equilibrium water content was defined
as the moisture content of films allowed to stand at ambient
conditions in the lab for 72 h (about 25.degree. C. and 70% RH).
The moisture content was measured by accurately weighing a sample
of film 10.2 centimeters.times.1.27 centimeters.times.63.5
micrometers (about 4 in.times.0.5 in.times.0.0025 in) before and
after a drying. Films were weighed (to 0.00005 g), dried in a
150.degree. C. oven for 4 h, and then immediately weighed to
determine the moisture loss. Equilibrium water content is the mass
lost upon heating divided by the mass of the dried film as a
percent.
[0253] Moisture absorption: Dried film samples (oven at 150.degree.
C. for 4 h) of known mass were submerged in water for 72 h at
ambient temperature (25.degree. C.). Following the time period, the
films were removed from the water and the excess moisture removed
by drying with a Kimwipe. Moisture absorption is the mass uptake
upon soaking in water divided by the weight of the dried film as a
percent.
[0254] Solubility: A positive result indicates that at a
concentration of 10% solids, the fully imidized film cast from the
poly(amic acid) solution dissolves in dimethylacetamide or
N-methylpyrolidinone (solvent indicated in the test) and can pass
through a 0.45 micrometer filter.
Example 47, Part A
Modification of Nano Clays.
Procedure for the Preparation of Organically Modified Clay:
[0255] The organically modified clay was prepared via ion exchange
in water or a combination of water and an alcohol, or water and
acetonitrile. The Na.sup.1 MMT (a clay with sodium counterions) was
dispersed in water or water/solvent combination at 1-5% by weight
and heated to 80.degree. C. The organic cation,
tetraphenylphosphonium bromide, was dissolved or dispersed water or
solvent combination as above in a ratio such that when the solution
or dispersion of the organic cation was added to the clay
dispersion there is organic cations equal to or in excess of the
cation ion exchange capacity of the dispersed clay. The mixture was
then heated to reflux for 1-2 h. Following cooling to room
temperature, the modified clay is collected by centrifugation. The
supernatant was poured off, and the solid modified clay was washed
by redispersing the clay in deionized water or deionized water
solvent combination and recollected by centrifugation. The wash
solution was poured off and the wash process is repeated twice
more. Following the final centrifugation, the solid clay was dried
in an oven and then ground to a fine powder.
Example 47, Part B
[0256] Detailed example: 2.0 g of NA.sup.+ MMT clay (cation
exchange capacity of 0.000926 mols Na.sup.+/g of clay; 0.001852
mols of cations total) was dispersed in 200 mL of a 50/50 mixture
of deionized water and ethanol and brought to reflux.
Tetraphenylphosphonium bromide (1.4167 g, 0.002216 mols) was added
and the dispersion was allowed to stir at reflux for two hours. The
mixture was cooled to room temperature and transferred to four 50
mL centrifuge tubes. The tubes were placed on a centrifuge and spun
at 3000 rpm for 5 min. The supernatant is poured off and
redispersing the clay in fresh mixture of 50/50 deionized water and
ethanol washes the remaining solid, and solid was again collected
again by centrifugation. The wash procedure was repeated twice
more. Following the final centrifugation and decantation the
remaining solid was dried in a 120.degree. C. oven for two hours
and then ground to a fine powder. Properties of Organic Modified
Montmorillonite Prepared from Aromatic Phosphonium Salts are shown
in Table 4.
TABLE-US-00004 TABLE 4 Wt loss on TGA 5% TGA under loss under Wt
loss at 400.degree. C. d-Spacing MW of N.sub.2 at 900.degree. C.
N.sub.2 under .sub.N2 for 30 min Modifier (Angstrom) modifier (%)
(.degree. C.) (%) TPP 17.8 339.4 25.0 449.0 3.1 ##STR00014##
Example 48
Detailed Experimental Method of Lowering the CTE of a Film Using
Aluminum(AcAc).sub.3
[0257] Soluble nanoparticle precursors:
Aluminum(acetylacetonoate).sub.3 was added to a solution of
poly(amic acid) prepared as above in any of examples 1-43, or a
solution of a soluble polyimide in DMAc to give a solution with
5-30% polyimide precursor or polyimide and 0.5%-31.8%
Al(acac).sub.3. The solution was then filtered onto a glass slide.
The coated substrate was then placed on the hotplate and subjected
to a thermal profile described in examples 1-43 as described above
to complete imidization. The films so formed were then removed from
the glass slide and used in later examples, or subjected to
analysis.
Example 49
Detailed Experimental Analysis of Adhesion of Films to Copper
[0258] Metal Adhesion: 2.54 centimeter square (one inch square)
film samples were sandwiched between two pieces of copper foil. One
piece of foil has a roughened granular surface to enhance adhesion,
the other copper surface was polished smooth. The stack was then
pressed between the parallel plates of a heated press at
421.degree. C. (790.degree. F.) for one minute with three tons of
pressure on the hydraulic ram. The adhesion of the film to copper
was then graded using a scale of 1-5. A one indicates no adhesion
to either surface. A two indicates moderate adhesion to the
roughened copper. A three indicates good adhesion to the roughened
copper surface, a four indicates good adhesion to the roughened
surface and moderate adhesion to the smooth surface. A five
indicates good adhesion to both copper surfaces equal to or better
than the benchmark films. The benchmark materials are GE resins
XH6050 extruded film and CRS5001 extruded film.
Example 50
Detailed Example of Solvent Cast Film with Nano Filler for Lowering
CTE
[0259] Cloisite 30B clay from Southern Clay was dispersed in
N,N-dimethylacetamide (DMAc) (13 g of clay in 5001 mL of solvent)
by high shear mixing with a Silverson mixer. The monomers,
4,4'-oxydiphthalic anhydride (0.5640 g), 4,4-diaminodiphenylsulfone
(0.3611 g), and oxydianiline (0.0903 g) were added to the clay
dispersion and the mixture was diluted with additional DMAc to give
a final mixture of 12.5% solids (polymer to solvent) and 3% filler
(clay to polymer). The vial was inerted with N.sub.2 and shaken
overnight to form a viscous polyamic acid solution. This solution
was then cast upon precleaned glass microscope slides and imidized
using the heating profile described previously. The resulting nano
filled polyimide film was peeled from the glass substrate for
testing. The resulting film had a T.sub.g=304C and a CTE of 44
ppm/C.
Example 51
Film Recycle Example:
[0260] Film scrap of example 6 (40ODPA/10BPDA//40DDS/10pPD) was
dissolved in 120.degree. C. DMAc at 5 wt % solids. The solution was
filtered through a 0.45-micrometer filter. The solution was then
cast upon a glass substrate and heated slowly on a hotplate
equipped with a ramp and soak temperature controller, a cover, and
a controlled nitrogen purge. The temperature was slowly raised to
200.degree. C. over 4 h maintaining a partial atmosphere of DMAc
vapor for the first three hours to control the solvent evaporation
rate. The resulting polyimide film was released from the glass
substrate by immersion in water and allowing the water to float the
film from the substrate.
Example 52
Film Recycle Example:
[0261] Alternatively the polyimide solution from example 51 was
combined with monomers to give a solution of polyimide and
poly(amic acid). 1.0 g of film from example 6 were dissolved in 7 g
of DMAc to give a solution of 12.5 wt % solids as in example 51. A
poly(amic acid) solution of example 6 was formulated and the two
solutions were combined to give a final solution of 12.5 wt %
solids. 1-20% of the composition resulting from redissolved scrap
film would be suitable for this procedure. The solution was then
cast upon a glass substrate and imidized with the thermal profile
in Example 1 and released from the substrate.
Example 53
Film Recycle Example:
[0262] Alternatively, the polyimide film scrap of example 6 was
ground to a powder using a mill and then blended with a
polyetherimide resin such as the GE resin XH6050 or other high
performance polymer (such as polyetherketone or polysulfone) by
first mixing the two powders in a shaker with up to 30% by weight
ground film scrap. The powder/powder blend was then extruded on a
single or twin screw extruder and pelletized. The blend was then
either molded into a finished part by injection molding or is
extruded into a film.
Example 54
Solubility Testing Examples: Applicable to any Films:
[0263] A piece of film with the formulation
40ODPA/10BPDA//40DDS/10pPD with a mass of 0.6420 g was added to a
vial containing 10 mL of dimethylacetamide. The vessel was inerted
with nitrogen and capped. The contents were heated at 120.degree.
C. for 24 h with gentle stirring. The solution after 24 h hours was
yellow in color with a slight haziness and no pieces of the film
remaining. The solution was then easily passed through a 0.45
micrometer filter with >90% of the solids content passing the
filter to give a yellow, transparent solution.
Example 55
Solubility Testing Examples: Applicable to any Film from Examples
1-43:
[0264] A piece of film with the formulation 50ODPA//50DDS with a
mass of 0.05834 g was added to a vial containing 1.080 mL of
N-methylpyrolidinone. The vessel was inerted with nitrogen and
capped. The contents were heated at 120.degree. C. for 12 h. The
solution after 12 h hours was dark amber in color and no pieces of
the film remaining. The solution was then easily passed through a
0.45-micrometer filter with >90% of the solids content passing
the filter to give a yellow, transparent solution.
Example 56
Solubility Testing Examples: Applicable to any Film from Examples
1-43:
[0265] A piece of film with the formulation 50ODPA//10DDS/40pPD
(example 29) with a mass of 0.3100 g was added to a vial containing
5.741 mL of dimethylacetamide. The vessel was inerted with nitrogen
and capped. The contents were heated at 120.degree. C. for 12 h.
The solution after 12 h was pale yellow in color and a substantial
amount of the film remained intact.
Example 57
Using Reactivity Differences to Make Blocky Polymers
[0266] On an analytical balance, 0.2657 g (0.903 mmol) of
3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was weighed
out to be with in 0.0005 g of desired value and 0.0977 g (0.9032
mmol) of para-phenylenediamine (pPD) was weighed out to be with in
0.0005 g of desired value. The monomers were transferred to a 20 mL
scintillation vial. The weigh paper is rinsed with 1.0 mL of
dimethylacetamide, ensuring complete transfer of the monomers to
the vial. More solvent (2.74 mL of dimethylacetamide) was
transferred by volumetric pipette to give a solution of the first
pair of monomers of the copolymer. The vial was inerted with
nitrogen by flowing nitrogen through the vial for one minute and
quickly capping the vial. The sample was then placed on the shaker
for 3 hours to form the poly(amic acid).
[0267] On an analytical balance, 0.4701 g (0.9032 mmol) of the
2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA)
was weighed out to be within 0.0005 g of desired value and 0.2243 g
(0.9032 mmol) of 4,4'-diaminodiphenylsulfone (DDS) was weighed out
to be within 0.0005 g of desired value. The monomers were
transferred into the 20 mL scintillation vial containing the
poly(amic acid) mixture prepared above. The weigh paper was rinsed
with 1.0 mL of dimethylacetamide, ensuring complete transfer of the
monomers and then 2.74 mL more of the dimethylacetamide was added
to give the final reaction mixture. This gave a solution of about
12.5% solids polyimide. The vial was inerted with nitrogen by
flowing nitrogen through the vial for one minute and quickly
capping the vial. The sample was then placed on the shaker for 12
hours to assure mixing.
[0268] Glass slides (Fisherbrand precleaned microscope slides) were
cleaned with hexanes. The solution (2.0 mL) was then filtered
through a 0.45 micrometer syringe tip filter onto the glass slide.
The solution coated glass slide was then placed on a hotplate
equipped with a ramp and soak temperature controller, a cover, and
a controlled nitrogen purge of 85 liters (3 cubic feet) per hour
(apparatus volume of 0.1 cubic feet). The sample was then imidized
using the thermal profile in Table 7.
TABLE-US-00005 TABLE 7 temp .degree. C. time (min) 25 0 40 45 40 60
120 90 120 120 160 150 160 165 200 180 200 195 300 210
[0269] Following imidization the film was released from the glass
slide by immersion in water at 25.degree. C., yielding a
freestanding polyimide film. The film was then submitted for
testing and analysis.
Example 58
Using Kinetics and Process Parameters to Make Block
Co-Polymers.
Two Vessel Method.
[0270] On an analytical balance, 0.0892 g (0.3033 mmol) of
3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) was weighed
out to be within 0.0005 g of desired value and 0.0328 g (0.3033
mmol) of m-phenylenediamine (MPD) was weighed out to be within
0.0005 g of desired value. The monomers were transferred to a 20 mL
scintillation vial (Vial#1). The weigh paper was rinsed with 2.0 mL
of dimethylacetamide, ensuring complete transfer of the monomers to
Vial #1. More solvent (1.0 mL of dimethylacetamide) was transferred
by volumetric pipette to give a solution of the first pair of
monomers of the copolymer. The vial was inerted with nitrogen by
flowing nitrogen through the vial for one minute and quickly
capping the vial. The sample was then placed on the shaker for 24
hours to form the poly(amic acid).
[0271] On an analytical balance, 0.6314 g (1.2130 mmol) of the
2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride (BPADA)
was weighed out to be within 0.0005 g of desired value and 0.3012 g
(1.2130 mmol) of 4,4'-diaminodiphenylsulfone (DDS) was weighed out
to be within 0.0005 g of desired value. The monomers were
transferred into a second 20 mL scintillation vial (Vial#2). The
weigh paper was rinsed with 1.0 mL of dimethylacetamide, ensuring
complete transfer of the monomers. More solvent (3.47 mL of
dimethylacetamide) was transferred by volumetric pipette to give a
solution of the second pair of monomers of the copolymer. The vial
was inerted with nitrogen by flowing nitrogen through the vial for
one minute and quickly capping the vial. The sample was then placed
on the shaker for 24 hours to form the poly(amic acid).
[0272] After mixing, the contents of Vial #2 was added to Vial#1
and rinsed with 2 mL of dimethylacetamide to ensure complete
transfer. The vial was inerted with nitrogen by flowing nitrogen
through the vial for one minute and quickly capping the vial. The
vial was placed on the shaker for 30 minutes. This gave a solution
of about 12.5% solids polyimide copolymer.
[0273] Glass slides (Fisherbrand precleaned microscope slides) were
cleaned with hexanes. The solution (2.0 mL) was then filtered
through a 0.45-micrometer syringe tip filter onto the glass slide.
The solution coated glass slide was then placed on a hotplate
equipped with a ramp and soak temperature controller, a cover, and
controlled nitrogen purge of 85 liters (3 cubic feet) per hour
(apparatus volume of 0.1 cubic feet). The sample was then imidized
using the thermal profile in Table 8.
TABLE-US-00006 TABLE 8 temp .degree. C. time (min) 25 0 40 45 40 60
120 90 120 120 160 150 160 165 200 180 200 195 300 210
Example 59
[0274] Using Preformed Imide Polymers and Process to Make Block
Co-Polymers. Two Vessel Method.
[0275] On an analytical balance, 0.6894 g (0.9408 mmol) of
Ultem.RTM.6050 (homopolymer of BPADA and DDS) was weighed out to be
within 0.0005 g of desired value, the polymer was transferred to a
20 mL scintillation vial (Vial#1). The weigh paper was rinsed with
2.0 mL of dimethylacetamide, ensuring complete transfer of the
monomers to the vial. More solvent (2.74 mL of dimethylacetamide)
was transferred by volumetric pipette to give a solution of the
polymer. The vial was inerted with nitrogen by flowing nitrogen
through the vial for one minute and quickly capping the vial. The
sample was then placed on the shaker for 12 hours.
[0276] On an analytical balance, 0.2782 g (0.8967 mmol) of the
4,4'-oxydiphthalic dianhydride (ODPA) was weighed out to be within
0.0005 g of desired value and 0.0970 g (0.8967 mmol) of
p-phenylenediamine (PPD) was weighed out to be within 0.0005 g of
desired value. The monomers were transferred into a second 20 mL
scintillation vial (Vial#2). The weigh paper was rinsed with 2.0 mL
of dimethylacetamide, ensuring complete transfer of the monomers.
More solvent (1.74 mL of dimethylacetamide) was transferred by
volumetric pipette to give a solution of the second pair of
monomers of the copolymer. The vial was inerted with nitrogen by
flowing nitrogen through the vial for one minute and quickly
capping the vial. The sample was then placed on the shaker for 12
hours to form the poly(amic acid).
[0277] After mixing, the contents of Vial #2 was added to Vial#1
and rinsed with 1 mL of dimethylacetamide to ensure complete
transfer to Vial #2. The vial was inerted with nitrogen by flowing
nitrogen through the vial for one minute and quickly capping the
vial. The vial was placed on the shaker for 6 hours. This gave a
solution of about 12.5% solids polyimide copolymer.
[0278] Glass slides (Fisherbrand precleaned microscope slides) were
cleaned with hexanes. The solution (2.0 mL) was then filtered
through a 0.45-micrometer syringe tip filter onto the glass slide.
The solution coated glass slide was then placed on a hotplate
equipped with a ramp and soak temperature controller, a cover, and
controlled nitrogen purge of 3 cubic feet per hour (apparatus
volume of 0.1 cubic feet). The sample was then imidized using the
thermal profile in Table 9.
TABLE-US-00007 TABLE 9 temp .degree. C. time (min) 25 0 40 45 40 60
120 90 120 120 160 150 160 165 200 180 200 195 300 210
[0279] Following imidization the film was released from the glass
slide by immersion in water at 25.degree. C., yielding a
freestanding polyimide film. The film was then submitted for
testing and analysis.
Example 60
Using Preformed Imide Prepolymer or Polymer and Process to Make
Random Co-Polymers, Ambient Temperature Method:
[0280] On an analytical balance, 0.9255 g (1.2630 mmol) of
Ultem.RTM.6050 (homopolymer of BPADA and DDS) was weighed out to be
within 0.0005 g of desired value and 0.0326 g (0.3018 mmol) of
m-phenylenediamine (MPD) was weighed out to be within 0.0005 g of
desired value. The polymer and diamine were transferred to a 20 mL
scintillation vial (Vial#1). The weigh paper was rinsed with 2.0 mL
of dimethylacetamide, ensuring complete transfer of the monomers.
Water (0.01 mL) and more solvent (4.98 mL of dimethylacetamide)
were transferred by volumetric pipette to give a solution of the
polymer and diamine and water. The vial was inerted with nitrogen
by flowing nitrogen through the vial for one minute and quickly
capping the vial. The sample was then placed on the shaker for 24
hours. (The mixture can optionally be heated at this point to about
50.degree. C. while shaking to aid the randomization reaction).
[0281] After the 24 hours, 0.0936 g (0.3018 mmol) of the
4,4'-oxydiphthalic dianhydride (ODPA) was weighed out to be within
0.0005 g of desired value. The dianhydride was transferred into the
20 mL scintillation vial (Vial#1). The weigh paper was rinsed with
1.49 mL of dimethylacetamide, ensuring complete transfer of the
monomer. The vial was inerted with nitrogen by flowing nitrogen
through the vial for one minute and quickly capping the vial. The
sample was then placed on the shaker for 12 hours to form the
random poly(amic acid). This gave a solution of about 12.5% solids
polyimide copolymer.
[0282] Glass slides (Fisherbrand precleaned microscope slides) were
cleaned with hexanes. The solution (2.0 mL) was then filtered
through a 0.45 micrometer syringe tip filter onto the glass slide.
The solution coated glass slide was then placed on a hotplate
equipped with a ramp and soak temperature controller, a cover, and
controlled nitrogen purge of 85 liters (3 cubic feet) per hour
(apparatus volume of 0.1 cubic feet). The sample was then imidized
using the thermal profile.
TABLE-US-00008 TABLE 10 temp .degree. C. time (min) 25 0 40 45 40
60 120 90 120 120 160 150 160 165 200 180 200 195 300 210
[0283] Following imidization the film was released from the glass
slide by immersion in water at 25.degree. C., yielding a
freestanding polyimide film. The film was then submitted for
testing and analysis.
Examples 61-85
Examples 61-85 Listed in Table 11 were Prepared According to the
Method Described for Examples 1-43.
[0284] Casting Procedure: The correct mol ratios of dianhydride and
diamine as shown in Table 11 were weighed on an analytical balance
to four decimal place accuracy.
TABLE-US-00009 TABLE 11 Dianhydrides Diamines ODPA BPDA BTDA BPhDA
PMDA BPADA DDS PPD 133APB 134APB MPD ODA Ex. Solvent (%) (%) (%)
(%) (%) (%) (%) (%) (%) (%) (%) (%) 61 DMAc 50 0 0 0 0 0 50 0 0 0 0
0 62 DMAc 45 0 5 0 0 0 50 0 0 0 0 0 63 DMAc 5 0 45 0 0 0 50 0 0 0 0
0 64 NMP 45 0 0 5 0 0 50 0 0 0 0 0 65 NMP 0 0 45 5 0 0 50 0 0 0 0 0
66 DMAc 45 0 0 5 0 0 50 0 0 0 0 0 67 DMAc 50 0 0 0 0 0 50 0 0 0 0 0
68 DMAc 50 0 0 0 0 0 40 0 0 0 10 0 69 DMAc 50 0 0 0 0 0 40 10 0 0 0
0 70 DMAc 50 0 0 0 0 0 40 0 0 0 0 10 71 DMAc 50 0 0 0 0 0 10 0 0 0
40 0 72 DMAc 50 0 0 0 0 0 10 40 0 0 0 0 73 DMAc 50 0 0 0 0 0 10 0 0
0 0 40 74 DMAc 50 0 0 0 0 0 40 0 0 10 0 0 75 DMAc 50 0 0 0 0 0 10 0
0 40 0 0 76 DMAc 50 0 0 0 0 0 5 45 0 0 0 0 77 DMAc 45 5 0 0 0 0 50
0 0 0 0 0 78 DMAc 45 5 0 0 0 0 10 40 0 0 0 0 79 DMAc 40 0 10 0 0 0
50 0 0 0 0 0 80 DMAc 0 0 0 0 0 50 50 0 0 0 0 0 81 DMAc 50 0 0 0 0 0
45 5 0 0 0 0 82 DMAc 50 0 0 0 0 0 25 25 0 0 0 0 83 DMAc 45 5 0 0 0
0 30 20 0 0 0 0 84 DMAc 45 5 0 0 0 0 30 20 0 0 0 0 85 DMAc/ 50 0 0
0 0 0 50 0 0 0 0 0 NMP
[0285] The monomers were then transferred to a scintillation vial
and the weigh paper used was rinsed with the solvent. The remaining
volume of solvent was transferred to the vial and the vial was
rendered inert with nitrogen. The sealed inert vial was then placed
on a shaker overnight to produce a poly(amic acid) solution. The
poly(amic acid) solution is then drop cast through a
0.45-micrometer filter onto clean glass slides, prepared in advance
by cleaning with hexanes.
[0286] The coated slides were then placed on a hotplate equipped
with: a thermocouple; a ramp and soak temperature controller; a
nitrogen purge; and, a cover. The films were then imidized
following the heating profile outlined in FIG. 1 and Table 2.
[0287] Upon completion of the imidization reaction, the films so
produced were removed from the glass slide for use in later
examples, or for thorough property testing. The physical property
measurements for Examples 61-85 are listed in Table 12.
TABLE-US-00010 TABLE 12 Tg Equilib Moisture Tg (DSC) CTE (DMA)
Metal moisture absorption Ex. Solvent Run 1 Run 2 (ppm/.degree. C.)
(.degree. C.) Adhesion (%) (%) 61 DMAc 302 42 318 62 DMAc 340 314
45 323 63 DMAc 292 327 50 334 64 NMP 343 65 NMP 312 42 326 66 DMAc
293 41/44 307 3 1 2.2 67 DMAc 319 47 324 5 1.5 3.3 68 DMAc 298 48
69 DMAc 301 47 311 70 DMAc 278 48 71 DMAc 294 43 73 DMAc 343 75
DMAc 214 48 217 76 DMAc 298 19 77 DMAc 213 51 78 DMAc 243, 295 226,
310 46 79 DMAc 231, 303, 340 45 80 DMAc 248 52 81 DMAc 47 82 DMAc
44 83 DMAc 42 84 DMAc 36 85 DMAc/ 294 NMP
Example 86
FPC Example
[0288] On an analytical balance, 11.3387 g of 4,4'-oxydiphthalic
anhydride, 1.8151 g of diaminodiphenylsulfone and 3.1620 g of
para-phenylene diamine were weighed out to be with in 0.0005 g of
the desired weight. The monomers were transferred to a 100 mL vial,
rinsing the weigh paper with 2.0 mL of dimethylacetamide, to ensure
complete transfer of the monomers. The remaining solvent (55.63 mL
of dimethylacetamide) was transferred by volumetric pipette to give
a solution of 12.5 weight % solids. The vial was rendered inert by
flowing nitrogen through the vial for one minute and then quickly
capping the vial. The sample was then placed on the shaker
overnight to form a poly(amic acid) solution.
[0289] Using a syringe and a 0.45 micrometer filter, 5 mL of
solution was then transferred onto a piece of smooth metallic
copper foil 10.2 centimeters.times.20.4 centimeters, 50.8
micrometers thick (4 inch.times.8 inch, and 2 mil thick)
pre-cleaned with isopropanol and drawn into a thin uniform coating
using a 381 micrometer (15 mil) wet film applicator. The sample was
then imidized using the thermal profile outline described above for
examples 1-43 and detailed in Tables 2 and FIG. 1 giving a
polyimide/copper laminate.
[0290] The laminate was then masked with scotch tape to give a
pattern of exposed copper lines of varying width (from 1 mm to 5
mm). The exposed copper was then etched with concentrated nitric
acid for one minute followed by washing with deionized water
yielding a patterned laminate with discrete copper conductors.
Example 87
Wire Wrap Example #1
[0291] A film was prepared from the composition 45%
4,4'-oxydiphthalic anhydride, 5% 3,3',4,4'-biphenyltetracarboxylic
dianhydride and 50% diaminodiphenylsulfone prepared as above. The
film was cut into strips 1 mm wide and 5 cm in length. The strip of
film was affixed to a 16 gauge stainless steel wire at a 45 degree
angle relative to the wire with a piece of tape. The stripped was
then tightly wrapped with 0.1 mm overlap at the edge to provide a
high heat, flexible, insulating coating around the wire.
Example 88
Capacitor
[0292] A 7.62 centimeter.times.7.62 centimeter (3''.times.3'')
piece of film (prepared from the composition 40% 4,4'-oxydiphthalic
anhydride, 10% 3,3',4,4'-biphenyltetracarboxylic dianhydride and
10% para-phenylene diamine and 40% 4,4'-diaminodiphenylsulfone, as
above using a 381 micrometer (15 mil) doctor blade) was placed
between to pieces of 5.08 centimeters.times.5.08 centimeters
(2''.times.2'') copper foil. The stack was then pressed between the
parallel plates of a heated press at 404.degree. C. (760.degree.
F.) for one minute with three tons of pressure on the hydraulic
ram. The resultant article, which has an adhesion ranking of 4 by
the test described previously, is a capacitor consisting of two
parallel conductors separated by thin polyimide insulator.
[0293] All patents, patent applications, and other publications
disclosed herein are incorporated by reference in their entirety as
though set forth in full.
[0294] While the invention has been described with reference to
preferred embodiment, it will be understood by those skilled in the
art that various changes may be made, and equivalents substituted,
for elements thereof without departing from the scope of the
invention. In addition, many modifications may be made to adapt a
particular situation or material to the teachings of the invention
without departing from the essential scope thereof. Therefore, it
is intended that the invention not be limited to the particular
embodiments disclosed as the best mode contemplated for carrying
out the present invention, but that the invention will include all
embodiments falling within the scope of the appended claims.
* * * * *